Dear all,
I´m about to go completely bezerk over my -89 Cherokee.
Been here "many o´times" with this problem before, but without sucess so far. -So I´ll give it another go. Here here are the symptoms:
¤ Always starts up fine. No problemos
¤ Runs OK, when cold (Not Great, but OK")
¤ Low idle, about 600-850rpm. And a bit jumpy and jerky. Up and down, up and down...
¤ As soon as engine starts to get a bit hotter, let´s say after ca 1-1½min, It starts to run a bit worse, but not terrible.
¤ Engine keeps stalling for no apparant reason!!! Quite often actually. But always starts up without hesitation again. Just turn the key.
¤ Found that it normally happens when easing or letting go of the gaspedal. As long as I keep accelerating it runs fairly fine, but as soon as I let go of the gaspedal or ease on it, It dies just like somone turned off the ignition key. But its only the engine that dies, all the other electric system is fine and keeps on working. So while still rolling I just put gear in "N" and start her up again. -And it seldom happens whith cold engine.
These are the things I´ve checked, replaced, or in other way ruled out. A friend has one of same year and model, so I have tried components from his car at some points to rule out defective ones on mine.
Cleaned out throttlebody
TPS
Flywheel sensor (CPS?)
EGR valve
Fuelfilter
Ignition module/coil
Sparkplugs+cables
Rotor+cap
Fuel resistor? (white ceramic, found in inside fender, drivers side)
New "Red Top" battery
New intake manifold
Visually checked vacuum hoses
Since the problem seldom happens when engine is cold and seems to be related to when engine starts to get warm or has reached normal working temp, I´m thinking some kind of sensor telling the computer to switch from "cold engine" to "normal working mode" or such. Perhaps some temperature related sensor?
I´ve been told by a Chrysler mechanic that not all sensors are in operation until engine has reached working temp? Anyone know?
I found a link here before, to a site where one can find specs on all sensors in the 4.0L engine, and also how to check them with the voltmeter. But I can´t find it again.
If there´s anyone whith an idea, tip or trick to faulty diagnosis?
I´d be so grateful!