I’ll start by saying that I've had my Cherokee (97, 4.0) almost a year now, It's the best car I've ever owned and I love everything about it. I know if I can fix this, I'll be totally sold for life; I've done a lot of reading on forums and Reddit and tried to solve this problem myself. However I can’t get to the bottom of it and I'm on the brink of getting rid of it on the grounds of safety.

I should reiterate that I really love XJs, even though they arent common here in the UK and its not easy or cheap to get parts. But it’s getting to a stage where I almost can't live with it now, please convince me to stay the course.

The problem is, at idle or as come to a stop the RPMs will drop and the engine will die. I have to bump it into neutral, feather the gas to keep the revs up and coast to a stop while braking, It doesn't do it every time but its close to 50%. Seems to be totally random, whether hot/cold etc.

This is a massive pain in the *** and it’s really testing my love for the Jeep. Not only that but its ****ing dangerous too. All the time its moving is absolutely fine, it’s just when you try to stop.

If the engine does stall I have to put it in neutral, hold the gas pedal about ¾ of the way down and rock it back and forth while turning the key to restart the engine. It will splutter and strain but eventually restart. Just turning the key will just crank the engine till the battery dies.

However if I turn the engine off with the key (as normal) it starts back up absolutely fine. So I only have to feather the gas to start it when it stalls, not every time I start it. (this is the strangest part to me)

Things I've changed less than 500 miles ago;

• Plugs
• Coil
• Leads
• Cam Position Sensor/ Switch plate
• Rotor
• Cap
• TPS
• Cleaned IAC
• Cleaned all grounds and battery terminals

Things I think it could be?

• Fuel pump?
• CPS?
• Bad battery / Terminals or connection?
• IAC?
• O2 Sensor?

Any advice guys? Please convince me to keep the Jeep, I love it but I've been battling this for best part of a year and I'm close to sticking it on eBay.

 

You cleaned the IAC, but what about the throttle body throat and butterfly?

Check your intake manifold bolts to make sure they're snug first chance you get.

You could also have a faulty IAC.

 

Faulty O2s will cause strange things.

Don't forget you have two of them.

 

Right. Wouldn't hurt to scan it also to see if there's something wrong not throwing a code.

 

I've removed the entire throttle body and cleaned it along with the IAC. The top bolts on the exhaust manifold are definitely tight because I checked them last night. I'll check the lower ones tonight.

I should have mentioned, there are no codes present nor is there a CEL at any point. I've got a cheap OBDII scanner which works with Torque, however it will not connect to my ECU for some reason.

 

Just for fun, how about refreshing all the connectors in the engine bay by disconnecting them, blowing them out with electronics cleaner and plugging them back in. Every one you can see.

You could also have a bad IAC. electrical things can be very intermittent.

 

Thanks Cruiser, I'll try this tonight too.

 

Keep us in the loop.

 

Ok guys, I checked the lower manifold bolts last night and they are definitely all tight, I couldn't even get a quarter of a tun on any of them.

I've cleaned out every electrical connection I could see, I even went underneath and got to the O2 sensor connections (I wanted to check the wiring anyway).

It was marginally better last night afterwards, however it's right back to the same symptoms this morning. After some (even) further reading I'm wondering about these O2 sensors.

http://www.naxja.org/forum/showthread.php?t=1046465

This thread mentions some symptoms that ring true;

-When it finally does start it wont stay idling, I have to double foot it until I get on the road again.
-If I jab the throttle it acts like it wants to die(don't know if that's related)
- there is often a fain smell of gas under the hood and in the cab at start up.

Parts on RockAuto are £50 for up and downstream NTK OM replacements, is it worth a shot?

 

Grimmshank were you ever able to figure out your issue? My jeep is having the exact same symptoms as what you described.

Thanks!

 

Hello mtbfreak612,

We know you're going to get some great advice. Just to chime in, if you decide to go into the dealership to get this checked out, let us know. We're available via direct message and would be happy to get this escalated for further handling.

Jasmine
Jeep Social Care Specialist

 

Those symptoms have the hallmarks of a torque converter clutch that is not disengaging properly and dragging the motor down to stall as the drive-line is slowing/stopping.

I'm going to link a site that was written for GMs, but the descriptions were well written. Particularly, check out the "Transmission Converter Clutch" section.

https://www.thoughtco.com/diagnosing...roblems-262653

I tried to find a Jeep specific description, but this one explains it just as well.

 

Ill look into it thank you, however I threw a new cap and rotor along with new plugs and wires in and it seems to have cured it although time will tell.