mtnance

96 Jeep. 4.0

This has been a growing problem, now it's all the time. When I do start the car (sometimes after it's been sitting, sometimes after it's idled a bit, it dies/stalls out when in gear but never in idle. Past few days I've been driving and it stalled at traffic light, tonight in the driveway. Here's what happened tonight. Once it started either in park or neutral and I just barely touch the acc pedal, it stumbles bad and if I let off the pedal, it would go into a high idle then drop down to normal idle and idle fine. If I put it in gear, (with brake on) it seems to stumble some, but try to press the acc pedal and it tries to die. If I don't let up, engine dies. Then I can't get it started for 5 or 10 minutes.

Changed sensors, etc.

I need help here, anyone have a clue what I can check? I do not have a multimeter, etc

Ant.

Well I am thinking it is a fuel problem you are having,


check fuel pressure at the rail..

Ant...

kjc

The idle air control (IAC) valve is the component that holds it to a nice steady idle, I think at about 700rpm on yours? If you touch the go pedal, the IAC takes a break, and the Throttle position sensor (TPS) takes over. You need a meter to test the TPS, or you can just replace it. But before you join the "throw parts at it til it works" club, check all vacuum hoses and especially the ends where they connect. Your symptoms could very well be due to a simple vacuum leak. Post back anything you find out.

If you want to diagnose and fix your Jeep, you're going to need a few basic tools, otherwise, just save your pennies and pay a shop to figger it out

mtnance

Well, I did figure it out but I did probably did buy a few unnecessary parts in the process. I figured $250 out of my pocket before I had to give up. That's 3 hours labor for a shop.

It ended up being an ignition coil that was kicking in and out. I tested the thing twice during my "battle" and both times, I had spark. The final night before giving up, it wouldn't start but would turn over, so I immediately tested the coil for a third time and wouldn't you know,...no spark. Got a new one and we're good to go.

I had replaced the TPS and the IAC because I had never touched them before and thought, perhaps....

I also dropped the tank and installed a new fuel pump and fuel pressure valve. I realize it wasn't needed at the time, but the way I look at it, it's all new under there now so I shouldn't have an issue for a long time.

The fuel pressure valve shows on many diagrams to be on the fuel rail, but in this case, it's on top the fuel pump. Took a little tedious prying to avoid snapping plastic parts, but it's all good.

The only thing not replaced (in the past year) are the fuel injectors. I've been told these really don't go bad that often and when they do, it's like a fouled plug and unless they all go at the same time, you should be able to get back home.