I've been battling with this issue for a month and have spent a lot of money trying to figure why my 96 jeep gc laredo 4.0 inline 6 181k is stalling.

It starts perfectly, idles perfectly. Sometimes on idle I have seen the idle just rise all of a sudden. Vacuum leak?

When I'm driving the rpm's will go near 0 for a few seconds and then resume normally to the correct rpm, acceleration is disabled at this point. Sometimes I'm lucky and it will resume, other times it just dies.

I've sat at a light and have seen the engine actually die and come back to life.

After stalling, I have tried to start it but would take 5-10 seconds to start.

This is a completely random event. I am receiving no codes.

I have replaced the IAC, TPS, CPS, Coolant Temp Sensor, Ignition Coil, Plugs and Wires, Air and Fuel Filter.

I am close to driving this thing off a cliff. It's driving me nuts.


PS. I must also mention that most of stalling and bucking occurs before reaching maximum temp of 190*. Once the coolant temp is at full temperature it does not stall at all. I can drive all day and be just fine. It's only when I am having issues is when the temp is climbing to 150*. I have confirmed this.

 

those things are prone to having the exhaust manifold crack. check there. also classic symptoms of a bad fuel pump. check the fuel pressure.

 

my moms jeep has the same problem,we cant figure it out either check the fuel pressure at the rail and it was readin around 50 psi strong....and when ever it does throw a code its always a different code....once it threw a seconday ignition code....still dont know wat that means....if u find out wat it is let me kno.....btw she only has 110,xxx on a '96

 

sounds like you need to go to the stealership so they can put a good scanner on it to see what the voltage is on some of those sensors.

 

Thats what Im betting. Ive never seen a 4.0 exhaust mani/ header that wasnt busted down by the collector. Very common problem. Itll suck in fresh air and freak the O2s out and then wig out the whole deal.

 

Well, to let others know what it was that was causing the stalling...it turned out to be a PCM that was shorting out. The PCM is located behind the reservoir/coolant tank in the engine area. I had the PCM programmed by a Jeep dealership. So all in all, I spent a nice $1,000 in parts, sensors, and labor. Replaced TPS, IAC, crank sensor, coolant temp sensor, thermostat and housing, pick-up coil, ignition coil, spark plugs and wires, fuel and air filter. This Jeep is practically new!

 

if ya want i can put it on my scanner and see whats going on.. these trucks have computer problems..if so i can get a used compter and program it to your truck.. let me know