94GC&03GT

Hey guys im new to the forum, bout 3 weeks ago picked up a 94 Grand Cherokee, ZJ, 5.2L. Got it for 1000 with the body in 9 out of 10 condition and running 8 out of 10. Noticed a Misfire so i did everything, plugs, wires, cap, rotor, air filter, oil change, fuel pump, fuel filter, flushed the tranny, new tranny fluid. Only thing i didn't do was injectors. I was told that the cpu's sometimes dont read properly and can cause a check engine light but ive noticed the light goes off sometimes and it fires all 8 cylinders. I tried some techron and marvel mystery oil also.

should i just get injectors, cause i saw them for 100 bucks on ebay?

Bustedback

Check the connections at the plugs on the injectors for loseness. A bad connection can cause an intermittant miss and the check engine light to come on.

94GC&03GT

yeah i check everyday, there always on tight, its had the miss since day 1 and the original spark plugs and wires were always tight.

truck sat inside a garage for over 5 years without starting, then i bought it and it started right up......

Bustedback

Are the injector wire harness connections tight at each injector?

SeriousOffroad

Your PCM completes the ground path for the injectors. Dirty grounds near the PCM might be the root cause of your problem.

94GC&03GT

yea connections are tight on the injectors, ill have to check the pcm.....

SeriousOffroad

Check the grounding points near the PCM as well as the ground wires themselves.

rickybarth

how do you clean the pcm connections

retreaded jeeper

run injector cleaner meantime while you're taking advantage of all other advice

SeriousOffroad

A spray can of Electrical Contact Cleaner followed by a little bit of Dielectric Grease.

94GC&03GT

yea i ran the techron and also marvel mystery oil too