1990 Cherokee 4.0L Stalling and Bucking Problems. Need advice.

I have a 1990 4.0L Cherokee that is having stalling and bucking
problems. While driving or coming to a stop the engine would stall, I
would hear a slight puff sound and then smell fuel in the engine
compartment. At other times, usually on acceleration, the engine would
buck. I had the vehicle towed 3-4 times to a shop and they checked the
fuel system, the fuel pump (it was bad and replaced), and the fuel
system power cleaned.
I have had the fuel pump replaced, the CPS replaced, the fuel system
(injectors cleaned), and had a rebuilt PCM put in. The intermittent
stalling continued and the engine would "buck" on acceleration like I
did not know how to drive a manual transmission vehicle. The PCM was
taken out and the original replaced (The reason the PCM was replaced
was that at times after the engine was turned off the fuel injectors
kept firing.)


After reading a number of posts on this group, I cleaned the
connections on both the Throttle Position Sensor (TPS) and the Input
Air Sensor (IAS) on the throttle. Upon restarting the vehicle, the
engine stopped stalling in my garage (Yes!) and I was able to drive it
without it stalling out for about 5 miles. It did buck a little and a
few times the RPM level dropped a little but did not stall. On the
drive back home it did not buck at all and the RPM level stayed
consistent even at stop lights.


I am hoping that the cleaning of the contacts on the TPS and IAS has
solved the problem, but I fear that it might be the PCM unit (see note
above).


Finally, after I had the Fuel Pump replaced, the fuel gauge stopped
working, at times it does come back on for a second, (which leads me
to think a short, or an electrical (ground) problem. Does the PCM have
anything to do with the Fuel Gauge? Should I request the shop that
replaced the fuel pump to fix the fuel sender or could this have
occured separately.


This morning when I drove to work, it was
doing it again. The RPM was fluctuating and it stalled once, but I was
able to start it rather quickly. I am wondering if I should purchase a
new TPS and/or IAS from the dealer or try to get one from a local
junkyard. Or I might clean the contacts a little better. Do you have
any suggestions on what I should use to clean the contacts. I am also
thinking of getting a PCM from the same jyard if I can find my year and
manual tranny.


Otherwise this has been a great vehicle and I do not want to give up on
it! Any other suggestions would be greatly appreciated.

Bad ground connections can cause all your problems, Theres nothing wrong with the ECU. I would look for bad ground connections at the fuel tank for the gauge and stalling problems.

Yes the fuel gauge not working after the pump replacement is related.

I had this happen to me on a 87 MJ 4 cylinder with manuel trans. The spark plugs was the problem. They were misfiring . The service manuel called it high speed glazing.Good luck