Issue With Stalling/Hesitating

[rogerbennett]

Hi, I'm a first-timer on here - I've got an ongoing problem with my Wrangler TJ Sahara. It's a 2000 model year, 4.0 auto-trans with 202k miles on it. I've owned it since 2002 when it had 18k miles. It has always ran great until the past year - now it randomly stalls/loses power and I can't find any reason for it. I can drive all the way on the freeway without problem, exit the freeway, stop at a stoplight and then it suddenly stalls while stopped. Other times it stalls while it's in motion. Sometimes it stalls completely and I need to pull over and restart it, other times it just hesitates for a second or two like it's not getting fuel, the RPMS will drop to zero and then it suddenly gets power again and keeps going. Sometimes the check engine light or check gauges light comes on and sometimes they don't. I can drive it all day and never have a single problem, other days it will have issues three or four times in one trip across town. I've had a friend who is a professional mechanic look at it, but have not taken it to the Jeep dealership yet, since I know from having worked at a dealership that intermittent problems like this can cost hours of diagnostic time and a lot of money. I figured I would check on here first.

I've already replaced the fuel pump, fuel pressure regulator and fuel filter (Delphi kit from Autozone), IAC (Idle Air Control) valve, battery terminals, ignition coil pack (late 2000 year distributor pack) and new plugs and battery terminals. I've always changed the oil religiously and also always put in good-quality 89 octane gas. I've also been using a variety of fuel system cleaning chemicals at each refill, hoping that will clear out any blockages or issues but they don't seem to help. I'm not even completely sure it is a fuel issue - maybe something in the engine or transmission?

Any advice would be appreciated!

 

[97TJ_305]

I'm having similar problems so I feel your pain.

I'm not an expert but I read that stalling could be related to the throttle cable so I did an easy adjustment today. It didn't fix the stalling but it fixed a hard shift between one of the gears. Worth a shot considering how easy it is.

Also cleaned the throttle body from other recommendations but that didn't work either.

 

[KCsTJ]

Have you checked your vacuum hoses?
When they get old they lose their grip on metal fittings or crack or break where they attach at the intake.
I would try to pull any engine codes.
I would also check your intake manifold bolts for proper torque.

 

[ac_]

So stop replacing parts. You may get lucky, but in the end you will probably spend more than all of that money not sending it to the dealer. It is possible the dealer can find the problem quickly. You could tell them to drive it around, and they won't charge you labor for driving it, but it does help if you can find a pattern. We might be able to help if you can find a pattern. By pattern, means a way you can duplicate it every time.

What codes are you getting? That should be your first point of reference.

If it stalls when you come to a stop intermittently, it could be that your torque converter is not unlocking. It could be from a bad torque convertor or a bad lockup switch. I am not in anyway saying that is your problem, but it is bad if it is and you spent all of your money replacing the fuel system.

In fact your fuel rail probably has a Schrader valve, and a cheap fuel gauge could have saved you some time and money.

The good thing is now you know it isn't the fuel system, and you probably are not going to have to worry about that now, but now you have to find what the real problem is.

I am not trying to make you feel bad, and as I read this back it might seem kind of harsh, but you wouldn't believe how many people spend a lot of money trying to fix something without asking for help first, and it was something they didn't even think to check. Sometimes it could be something we have all dealt with at some point. I feel bad because you spent all of that money for nothing right?

I am not saying I can help you, but I can try, and give you some free stuff to check to eliminate things right away. So there is where we are now.

Lets start with the codes: What codes do you see when/before this happens?

 

[tworley]

Lets start with the codes: What codes do you see when/before this happens?

X2. Quit throwing parts at it and read the codes. You can actually do that yourself by turning the key to the "on" position (dont start it!). On/off/on/off/on (within 5 seconds) and then wait a moment. If done correctly you will at least get code 55 on the odometer which means its done scanning.

 

[SaharaTJ01]

When you pull off the freeway and come to a stop and the tach starts to drop do you feel the engine rpm dropping as well? Or does the tach usually drop before the engine does? The crank sensor keeps time for fuel injection during open loop, once your jeep is warm it will go into closed loop mode and the cam sensor will take over. I have had multiple issues on different jeeps with these cam sensors being as they use bearings like a distributor and if the distance is changed between the magnets in the sensor, it may be contributing to you issue.