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1990 jeep cherokee 4x4 / 4.0l engine with automatic tranny. engine misses, seems like a bad plug or wire but all were replaced along with new rotor and cap.

this is a problem that has been slowing starting over the last few weeks. it would only do it after driving for awhile but now it happens as soon as you start the engine. engine does take an exxcess amount of turns before it starts.

parts that have been recently changed:

throtle position sensor
crank position sensor (top of tranny)
EGR valve and solinoid
spark plugs and wires
rotor and cap.

we suspect it might be the pickup coil under the rotor in the distributor and have ordered the part ($149 Can) but if anyone has any suggestions on what it might be please post.

thanks guy's!  

forgot to mention

no check engine lights are on, but im unsure if this model even has a check engine light

also, the O2 sensor was replaced too.  

update:

we purchased a 1989 2 wheel drive with a 4.0l engine for $150 in good runing condition (body rusted out).

swaped the entire distributor but it made no difference. so today we switched the ignition coil and all 6 fuel injectors. took it for a drive and all seems well. the engine idle's and drives really smooth so i'm hoping it was a bad injector.

if anyone needs parts shoot me an email! i live in northern ontario Canada.  

Hows the gas tank in it look? and is it a 5-speed?  

gas tank looks good. no leaks.

it's a automatic tranny. i will be bringing it to a wrecking yard soon so let me know if you need any parts. i'll be keeping the starter and rims for myself.  

how much would you want for the gas tank?  

I have the same jeep, although it is the Laredo, and my recent issue is the same as yours. My truck seems to miss but more noticeable in Drive rather than any other gears. It seems to almost be inexistant in any gear other than Drive.

I have had opinions from it being my wires to a bad cylinder. I wanted to mention that I also was told to check the drive plate of the truck. Where the Crank Position Sensor reads off of. Firstly, take off the starter and turn the motor while inspecting the drive plate to see if it is warped in any way or if it is missing extra teeth, other than the suposed couple. This could cause your brand new CPS to read wrong.

I haven't gotten that far with my truck yet but am interested ,almost pleeding, to know what is going on with your truck now-a-days?

-Azdezertrose286@aol.com if you want to let me in on the secret to fixing this jeep problem...  

most car parts stores sell coil output testers for under 10 bucks...  

i have fixed many misfire problems with a new coil that puts out enough voltage to fire the plugs..

also check the dist shaft for play.. i have seen a bunch of them that the upper bushing wears a lot... this moves the rotor off to one side away from the cap terminals...

beware.. always pay the core on the reman dist for a few days... while swapping it... i have had some problems with the cam sensor inside the remans being bad...  they just repair the bushing...

i have also had to clean the injectors on some..

the pcv system on 4.0's is a fixed orifice... the rear fitting in the valve cover...   the tiny plastic tube that connects it... also clogs...  the hoses are cheep at jeep.. under 20 bucks...
it comes the a new manifold pressure sensor hose taped in place.. do not remove the tape... it fits with them taped together..

with the hose unplugged...  a quarter turn and the elbow comes out for replacement ....