Rpm drop at higher speeds
12-05-2018, 07:49 AM
#1
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Year: 1998
Model: Cherokee (XJ)
Engine: Inline 6, 4.0
Rpm drop at higher speeds
So I just bought my XJ about a month ago. It’s a inline 6, 4.0. Had some minor problems. Cylinder 4/5 misfire which I found it to be the injectors. So I just replaced all of them. But what I have been noticing which is most concerning to me. Which I’m not sure is a normal issue. That when I get to about 60-70mph, first it is kind of wobbly. Which might just be a alignment issue or an arm issue. Which I plan to check both. But when I am at those speeds I’m at about 2300-2500 rpm. Which I have never owned a automatic whith 5 gears. So I’m sure that is probably normal. But when I let go of the accelerator it drops to about 1400-1500rpm. Now I have worked on my fair share of transmissions on my old dodge truck. I know that it’s not slipping or dropping gears when I let off the gas. But it will go right back up to its 2300-2500 rpms when I get back on it. Any ideas on what it could be or if it is even an issue.
on another topic, when I get on the gas hard the check engine light will flash. But never stays on. It only does this when I really rev it up to get up to speed. When I do it gradually there is no issue.
on another topic, when I get on the gas hard the check engine light will flash. But never stays on. It only does this when I really rev it up to get up to speed. When I do it gradually there is no issue.
12-05-2018, 11:13 AM
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Year: 1997
Model: Cherokee
Engine: 4.0
So I just bought my XJ about a month ago. It’s a inline 6, 4.0. Had some minor problems. Cylinder 4/5 misfire which I found it to be the injectors. So I just replaced all of them. But what I have been noticing which is most concerning to me. Which I’m not sure is a normal issue. That when I get to about 60-70mph, first it is kind of wobbly. Which might just be a alignment issue or an arm issue. Which I plan to check both. But when I am at those speeds I’m at about 2300-2500 rpm. Which I have never owned a automatic whith 5 gears. So I’m sure that is probably normal. But when I let go of the accelerator it drops to about 1400-1500rpm. Now I have worked on my fair share of transmissions on my old dodge truck. I know that it’s not slipping or dropping gears when I let off the gas. But it will go right back up to its 2300-2500 rpms when I get back on it. Any ideas on what it could be or if it is even an issue.
on another topic, when I get on the gas hard the check engine light will flash. But never stays on. It only does this when I really rev it up to get up to speed. When I do it gradually there is no issue.
on another topic, when I get on the gas hard the check engine light will flash. But never stays on. It only does this when I really rev it up to get up to speed. When I do it gradually there is no issue.
Aw4 trans is an automatic, it's a 4spd. You may think it's 5, because the torque converter locks up in od (this is normal) and the rpms drop, just like when it shifts. The rpm drop when you let off the gas sounds normal to me too. Flashing check engine light means misfires are happening.
12-05-2018, 04:53 PM
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Year: 1998
Model: Cherokee (XJ)
Engine: Inline 6, 4.0
What year is it?
Aw4 trans is an automatic, it's a 4spd. You may think it's 5, because the torque converter locks up in od (this is normal) and the rpms drop, just like when it shifts. The rpm drop when you let off the gas sounds normal to me too. Flashing check engine light means misfires are happening.
Aw4 trans is an automatic, it's a 4spd. You may think it's 5, because the torque converter locks up in od (this is normal) and the rpms drop, just like when it shifts. The rpm drop when you let off the gas sounds normal to me too. Flashing check engine light means misfires are happening.
its a 1998. So your your saying that the rpm drop is fine. And I just had the check engine light come on on the way home but nothing is popping up when I scan it. But my scanner is junk. So I’ll be getting a new one tomorrow.
12-05-2018, 04:57 PM
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Year: 1997
Model: Cherokee
Engine: 4.0
What part of pa are you from anyways? We've got a bunch all over that may be willing to give a hand if you ever need it. Check into the pa Cherokee club thread up in the stickies section if you want to too.
12-08-2018, 07:41 AM
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Year: 1998
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From what you explained, yes, sounds normal. Not sure what size tire you're on, but the rpm's at cruising speed sound right too. Post up the fault coffee when you scan it if you're not sure where to go with it.
What part of pa are you from anyways? We've got a bunch all over that may be willing to give a hand if you ever need it. Check into the pa Cherokee club thread up in the stickies section if you want to too.
What part of pa are you from anyways? We've got a bunch all over that may be willing to give a hand if you ever need it. Check into the pa Cherokee club thread up in the stickies section if you want to too.
I’m right above Harrisburg Pa, and as for the tires they are not any bigger then the stock size. I have alloy rims on it though. And got the new scanner and it came up with cylinder 4,5 misfire again. But I’m thinking it might be a fuel issue. Every time I put fuel cleaner fluid in it, it will take about a quarter tank for it to take. But after that the check engine light will go out. And will run great until I fill it up again and get on the gas. I got a new filter for the bottom of the pump. But if I’m wrong. I don’t think the fuel lines will corrode from the inside, right? And I’ll look into that other thread, thanks for all the help guys.
12-08-2018, 03:26 PM
#7
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If you decide the transmission shifting is not the cause, check the catalytic converter for plugged up. just a thought.
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