93 XJ with stumble / cut out at highway speeds
11-14-2016, 10:49 PM
#1
Newbie
Thread Starter
Join Date: Jul 2016
Posts: 16
Likes: 0
Received 0 Likes
on
0 Posts
Model: Cherokee
93 XJ with stumble / cut out at highway speeds
November 2016 post.
Hey there. This is one of my first times posting. Being a member of a couple of motorcycle owner forums, I know to SEARCH first. But I've searched and searched and I'm wanting some opinions.
My 93 XJ (with 126k miles, auto trans, 4WD) stumbles once at cruising and highway speeds and on VERY long highway inclines / hills. It's like a single hiccup. Like a solid stumble....noticeable enough for the passenger to feel it in their seat. It usually does it when it's lugging between 1500 and 2000rpm. Over 900 miles in three days, I'd guess it did this about 20 or 30 times total. So it's not every time and it's not always on long hills. It's hard to reproduce the problem. The first time I noticed it was on level ground going about 45mph. As this past weekend progressed, it seemed like I was more likely to get the problem though when I was lugging climbing very long gradual highway hills. And it's almost always just a single stumble. Occasionally it would double and triple stumble. But it's really not a sputtering and it doesn't backfire. I climbed all kinds of VERY steep forest service roads this weekend in low gear and I never noticed it stumbling in those lower gears at slow speeds. It'll climb hills like a boss. And I had to pass a slow car on the highway and it handled that with no problem. Seems like if I'm really stomping on the gas, it responds and never stumbles there.
One thing is I do think I've probably got too much slack in my kick-down cable. I feel like I have to STOMP on the gas to get it to shift down. Maybe that's why i'm more likely to notice this problem....because I'm lugging around at low RPM more than most.
Also....after searching lots of post, I think maybe one thing to try is to just go through and check to see that there aren't any loose wires under the hood. And then maybe REFRESH THE GROUNDS?
Please and thanks in advance for any input.
Hey there. This is one of my first times posting. Being a member of a couple of motorcycle owner forums, I know to SEARCH first. But I've searched and searched and I'm wanting some opinions.
My 93 XJ (with 126k miles, auto trans, 4WD) stumbles once at cruising and highway speeds and on VERY long highway inclines / hills. It's like a single hiccup. Like a solid stumble....noticeable enough for the passenger to feel it in their seat. It usually does it when it's lugging between 1500 and 2000rpm. Over 900 miles in three days, I'd guess it did this about 20 or 30 times total. So it's not every time and it's not always on long hills. It's hard to reproduce the problem. The first time I noticed it was on level ground going about 45mph. As this past weekend progressed, it seemed like I was more likely to get the problem though when I was lugging climbing very long gradual highway hills. And it's almost always just a single stumble. Occasionally it would double and triple stumble. But it's really not a sputtering and it doesn't backfire. I climbed all kinds of VERY steep forest service roads this weekend in low gear and I never noticed it stumbling in those lower gears at slow speeds. It'll climb hills like a boss. And I had to pass a slow car on the highway and it handled that with no problem. Seems like if I'm really stomping on the gas, it responds and never stumbles there.
One thing is I do think I've probably got too much slack in my kick-down cable. I feel like I have to STOMP on the gas to get it to shift down. Maybe that's why i'm more likely to notice this problem....because I'm lugging around at low RPM more than most.
Also....after searching lots of post, I think maybe one thing to try is to just go through and check to see that there aren't any loose wires under the hood. And then maybe REFRESH THE GROUNDS?
Please and thanks in advance for any input.
Last edited by scrabble; 02-20-2017 at 11:50 PM.
02-20-2017, 11:49 PM
#2
Newbie
Thread Starter
Join Date: Jul 2016
Posts: 16
Likes: 0
Received 0 Likes
on
0 Posts
Model: Cherokee
Okay... I'm going to resurrect from the grave my own thread because I am still having this problem, though I can revise a little bit the symptoms I'm having.
What I've done so far....
1. New Champion spark plugs this month.
2. New Denso plug wires this month.
3. New cap and rotor this month.
4. New fuel tank (old one was leaking at the seams). Unrelated. Fuel pump looked to be in good condition.
5. New FUEL FILTER. Wix brand.
It's a '93 XJ Sport with almost 127k miles.
Acceleration is GREAT. If you get all over the gas, I don't think I ever get a stumble or a buck. It's a stumble or a buck typically when at highway speeds and I'm beginning to head up a long hill on the highway. So when going from minimal throttle to some more throttle to get up a hill. Often at less than 2k rpms.
So this past weekend, I stopped for about 20 minutes and when I fired it back up it died. Then when I re-fired it, it idled horribly as I was coasting down the hill. I had to ride the brake and the gas to keep it from dying. But then it ran fine on back roads (gravel) again until I got back out on the highway and it would stumble occasionally. Idled fine the rest of the day. 200 mile day.
The dying (on Saturday) was like a vehicle with a vacuum leak. So I started looking for a vacuum leak this evening. EUREKA!!!! Found a line that looked like it had dang near been severed in two. Tiny line from the charcoal canister over to the vacuum fitting nearest the fuel pressure regulator. The break was in the right hand corner of the engine bay near the firewall. Line was barely attached, so there was no doubt it needed to be repaired. So I repaired it and test drove it. Over about 40 miles, it DID in fact stumble about half a dozen times. So now I'm thinking, "Do I have a SECOND VACUUM LEAK somewhere?" It didn't buck and snort like crazy like it had been doing. It had been getting to the point where it would sometimes be a stutter (bucking) when I was rolling down the highway. So in a way I feel like it's gotten a little better by me fixing that DEFINITE single instance of a vacuum leak tonight.
IT IDLES FINES. Idles fine hot and cold both. No idle issues.
The reason I think it seems like a vacuum issue is because if you get all over the gas, it'll GO! It doesn't present like a fuel delivery issue in that manner. It stumbles when I'm loping down the highway at minimal throttle (between 1500 and 2000 RPM) and then start to give it a little more throttle to climb a hill....and probably drawing a vacuum. My understanding is you don't draw much of a vacuum at wide open or close to wide open throttle, but do draw a vacuum when loping down the highway or coasting. It happens so consistently that I have almost gotten to where I can reproduce the symptom ON COMMAND. If I stomp on the gas and get it to downshift, it won't stumble. But if I baby the throttle just a bit to try and prevent it downshifting....basically letting it bog down, it'll often stumble at that point. I pretty much NEVER notice it happen when I'm running around at slow speeds on gravel and dirt roads.
I know this is a LONG post. But I've been dealing with this for about 1500 miles in some way out back country areas. I've got lots of data points.
What I've done so far....
1. New Champion spark plugs this month.
2. New Denso plug wires this month.
3. New cap and rotor this month.
4. New fuel tank (old one was leaking at the seams). Unrelated. Fuel pump looked to be in good condition.
5. New FUEL FILTER. Wix brand.
It's a '93 XJ Sport with almost 127k miles.
Acceleration is GREAT. If you get all over the gas, I don't think I ever get a stumble or a buck. It's a stumble or a buck typically when at highway speeds and I'm beginning to head up a long hill on the highway. So when going from minimal throttle to some more throttle to get up a hill. Often at less than 2k rpms.
So this past weekend, I stopped for about 20 minutes and when I fired it back up it died. Then when I re-fired it, it idled horribly as I was coasting down the hill. I had to ride the brake and the gas to keep it from dying. But then it ran fine on back roads (gravel) again until I got back out on the highway and it would stumble occasionally. Idled fine the rest of the day. 200 mile day.
The dying (on Saturday) was like a vehicle with a vacuum leak. So I started looking for a vacuum leak this evening. EUREKA!!!! Found a line that looked like it had dang near been severed in two. Tiny line from the charcoal canister over to the vacuum fitting nearest the fuel pressure regulator. The break was in the right hand corner of the engine bay near the firewall. Line was barely attached, so there was no doubt it needed to be repaired. So I repaired it and test drove it. Over about 40 miles, it DID in fact stumble about half a dozen times. So now I'm thinking, "Do I have a SECOND VACUUM LEAK somewhere?" It didn't buck and snort like crazy like it had been doing. It had been getting to the point where it would sometimes be a stutter (bucking) when I was rolling down the highway. So in a way I feel like it's gotten a little better by me fixing that DEFINITE single instance of a vacuum leak tonight.
IT IDLES FINES. Idles fine hot and cold both. No idle issues.
The reason I think it seems like a vacuum issue is because if you get all over the gas, it'll GO! It doesn't present like a fuel delivery issue in that manner. It stumbles when I'm loping down the highway at minimal throttle (between 1500 and 2000 RPM) and then start to give it a little more throttle to climb a hill....and probably drawing a vacuum. My understanding is you don't draw much of a vacuum at wide open or close to wide open throttle, but do draw a vacuum when loping down the highway or coasting. It happens so consistently that I have almost gotten to where I can reproduce the symptom ON COMMAND. If I stomp on the gas and get it to downshift, it won't stumble. But if I baby the throttle just a bit to try and prevent it downshifting....basically letting it bog down, it'll often stumble at that point. I pretty much NEVER notice it happen when I'm running around at slow speeds on gravel and dirt roads.
I know this is a LONG post. But I've been dealing with this for about 1500 miles in some way out back country areas. I've got lots of data points.
Last edited by scrabble; 02-20-2017 at 11:58 PM.
02-20-2017, 11:59 PM
#3
CF Veteran
Join Date: Mar 2010
Location: Broward County Fl.
Posts: 47,923
Likes: 0
Received 22 Likes
on
22 Posts
Year: 1989 xj sport 2dr
Model: Cherokee
Engine: 12 hole bosch Injectors
Did you ever adjust kick down cable ? Or check for codes even if theres no light a soft code can be stored with out a check engine light present.
Last edited by freegdr; 02-21-2017 at 12:01 AM.
02-21-2017, 12:01 AM
#4
Newbie
Thread Starter
Join Date: Jul 2016
Posts: 16
Likes: 0
Received 0 Likes
on
0 Posts
Model: Cherokee
thanks
Thanks for the response.
Yes, I did adjust the kick down cable. Felt like it maybe helped a little bit with overall shifting and such. But not a HUGE improvement.
This vehicle was extremely neglected. All the things I've replaced REALLY needed it. Plugs looked horrible as did the top contacts on the distributor cap.
Yes, I did adjust the kick down cable. Felt like it maybe helped a little bit with overall shifting and such. But not a HUGE improvement.
This vehicle was extremely neglected. All the things I've replaced REALLY needed it. Plugs looked horrible as did the top contacts on the distributor cap.
02-21-2017, 12:04 AM
#5
Newbie
Thread Starter
Join Date: Jul 2016
Posts: 16
Likes: 0
Received 0 Likes
on
0 Posts
Model: Cherokee
codes?
Mine is a '93. My understanding is that this is PRE- OBDII. I thought that meant I can't just go to O'reilly and get codes read. Am I wrong about that? I know it still has a computer, but I didn't think it gives readable codes by the lay joe.
02-21-2017, 12:09 AM
#6
CF Veteran
Join Date: Mar 2010
Location: Broward County Fl.
Posts: 47,923
Likes: 0
Received 22 Likes
on
22 Posts
Year: 1989 xj sport 2dr
Model: Cherokee
Engine: 12 hole bosch Injectors
Very easy to do....Write down codes then remove neg battery cable for at leas 15 minutes then hook cable back up. Then drive and cause stumble. Then check codes again. Click here-----
Last edited by freegdr; 02-21-2017 at 12:12 AM.
02-21-2017, 12:24 AM
#7
Newbie
Thread Starter
Join Date: Jul 2016
Posts: 16
Likes: 0
Received 0 Likes
on
0 Posts
Model: Cherokee
Holy *****!!!
Well, fudging Youtube. Makes sense. Youtube has shown me how to do everything else I've done to this vehicle. :-)
SERIOUSLY, thank you VERY much. That gives me at least something to go on instead of just opening the hood tomorrow evening and staring at the same vacuum lines I stared at for two hours tonight. Granted, I did find a DEFINITE VACUUM leak for my efforts. So it was time well spent.
But this new info about code reading gives me something else to try!
I'll do this at my earliest convenience and report back!
THANKS MUCH! Have a great night!
Well, fudging Youtube. Makes sense. Youtube has shown me how to do everything else I've done to this vehicle. :-)
SERIOUSLY, thank you VERY much. That gives me at least something to go on instead of just opening the hood tomorrow evening and staring at the same vacuum lines I stared at for two hours tonight. Granted, I did find a DEFINITE VACUUM leak for my efforts. So it was time well spent.
But this new info about code reading gives me something else to try!
I'll do this at my earliest convenience and report back!
THANKS MUCH! Have a great night!
Trending Topics
02-21-2017, 06:00 PM
#9
Newbie
Thread Starter
Join Date: Jul 2016
Posts: 16
Likes: 0
Received 0 Likes
on
0 Posts
Model: Cherokee
55
I "Ran the diagnostics" this afternoon.
Did the key on and off routine and the first and only code was 55. Tried it again just to be sure. 55 again.
My plan was to write all the bazillions of codes down and then clear them by unhooking the negative on the battery and then run till stumble and come back home and read the code. But I guess there's no reason to go run until stumble since it stumbled half a dozen times last night and there are ZERO codes showing today. Correct me if I'm understanding that wrong.
Thoughts?
Let me float my girlfriend's theory out there... She says the jeep is "just kidding me". So far, that's actually the best theory I've got. :-)
Did the key on and off routine and the first and only code was 55. Tried it again just to be sure. 55 again.
My plan was to write all the bazillions of codes down and then clear them by unhooking the negative on the battery and then run till stumble and come back home and read the code. But I guess there's no reason to go run until stumble since it stumbled half a dozen times last night and there are ZERO codes showing today. Correct me if I'm understanding that wrong.
Thoughts?
Let me float my girlfriend's theory out there... She says the jeep is "just kidding me". So far, that's actually the best theory I've got. :-)
02-21-2017, 07:37 PM
#11
Newbie
Join Date: Feb 2017
Posts: 23
Likes: 0
Received 0 Likes
on
0 Posts
Model: Cherokee
How about the ignition coil? Also OBDII started in 96 OBDI was before that you should be able to check codes with scanner. hookup will be under the hood, different connector than OBDII You can also get engine data there if you have access to a scan tool.
02-21-2017, 09:54 PM
#12
Newbie
Thread Starter
Join Date: Jul 2016
Posts: 16
Likes: 0
Received 0 Likes
on
0 Posts
Model: Cherokee
Thanks, CornFed.
I have not checked the ignition coil. I had not gone that route because mine seems to fire up consistently every time. It didn't seem to match symptoms for that, but it wouldn't hurt me to look further down that road.
As for the OBDI scan, I called Oreilly and they said they could scan it for me, so I may go that route this weekend. There's an AutoZone and an Advanced very close by me too, so I could go to them as well. I wonder if a scan would reveal codes when the check engine light reading trick revealed no codes?
I have not checked the ignition coil. I had not gone that route because mine seems to fire up consistently every time. It didn't seem to match symptoms for that, but it wouldn't hurt me to look further down that road.
As for the OBDI scan, I called Oreilly and they said they could scan it for me, so I may go that route this weekend. There's an AutoZone and an Advanced very close by me too, so I could go to them as well. I wonder if a scan would reveal codes when the check engine light reading trick revealed no codes?
02-22-2017, 06:11 AM
#13
CF Veteran
Join Date: Mar 2010
Location: Broward County Fl.
Posts: 47,923
Likes: 0
Received 22 Likes
on
22 Posts
Year: 1989 xj sport 2dr
Model: Cherokee
Engine: 12 hole bosch Injectors
They way you checked codes is fine. Pull the coil wire and exam coil for heat cracks. A bad tps can cause similar issue.....https://www.cherokeeforum.com/f2/bad...ymptoms-41138/
Last edited by freegdr; 02-22-2017 at 06:19 AM.
02-22-2017, 09:35 AM
#15
Newbie
Thread Starter
Join Date: Jul 2016
Posts: 16
Likes: 0
Received 0 Likes
on
0 Posts
Model: Cherokee
thanks
freegdr...
I think I had read both of those posts about TPS symptoms. Last night, I searched the forum for "Highway stumble" and read anything and everything I could find. And from everything I've read (including the links you posted), yes, it sounds closest to the symptoms of a bad TPS...though not exactly.
I will examine the coil and may even see if I can test it.
Like a lot of folks say, I hate to start throwing new parts at a problem if I don't know what the problem is. But maybe if I can find one cheap enough perhaps it would be worth the gamble.
Let me ask this...
1. Do you think the symptoms warrant me checking the fuel pressure with a gauge? I don't know how to do that but I know it's a thing.
2. What about the fuel pressure regulator? Any reason to suspect that? I've examined the little 90 degree rubber elbow vacuum fitting attached to the fuel pressure regulator and it seems okay. It's a little dry rotted, but not awful and not crumbling.
Thanks again for the input! I appreciate it.
I think I had read both of those posts about TPS symptoms. Last night, I searched the forum for "Highway stumble" and read anything and everything I could find. And from everything I've read (including the links you posted), yes, it sounds closest to the symptoms of a bad TPS...though not exactly.
I will examine the coil and may even see if I can test it.
Like a lot of folks say, I hate to start throwing new parts at a problem if I don't know what the problem is. But maybe if I can find one cheap enough perhaps it would be worth the gamble.
Let me ask this...
1. Do you think the symptoms warrant me checking the fuel pressure with a gauge? I don't know how to do that but I know it's a thing.
2. What about the fuel pressure regulator? Any reason to suspect that? I've examined the little 90 degree rubber elbow vacuum fitting attached to the fuel pressure regulator and it seems okay. It's a little dry rotted, but not awful and not crumbling.
Thanks again for the input! I appreciate it.