I have a 95 z28 motor n my 94 ta, I bought it and it had a misfire n 2 cylinders so I changed plugs wires cap and rotor and still misfire then I did new head gaskets and laped the valves cleaned and replaced all bad wire connectors on the engine wire harness and still missfire! There is no check engine light on and the spark plugs are clean when I pull them after running the motor. I'm realy loosing my mind chasing this problem. It's a misfire in 2 cylinders. Can someone pls give me some advise on wat to do!

 

O ya and I put n new injectors.

 

u sure those 2 wires aint crossed? maybe the injector wires are crossed?

 

icm, coil, opti harness connection pigtail thing?

 

Double check your firing order

 

Have you used a noid light to see if each injector lead is getting power?

 

if its 7 and 8, check your EGR... mine was stuck open and those two cylinders were sucking pure exhaust and missing like a SOB

 

Thank u all for ur advise, I double checked the fireing order and the wires are correct and I took the time to run them the stock way. I did check the power to the injectors with an ohm meter too, it is 4 and 6 that r misfiring. I inspected the crap outa the wiring harnass and I'm pretty possitive I replaced all the cracked wires and bad wire clips, I haven't replaced the coil tho can that cause just 2 cylinders to misfire? I checked for spark and I am getting spark n both those cylinders too, is it posible that they r sparking at the wrong time? Again thank u for ur advise.

 

I just took off my coil and there is a bunch of white stuff between the the top the metal on it, and there is no grease on it anymore should I get a new one or just clean this one up? There is also white stuff on the terminal where the coil wire goes from the coil to opti

 

thats dielectric grease. is it dirty?

 

Ya it's dirty it looks more like it's battery acid and the terminal where the coil wire goes looks all chewed up. It looks like someone dropped it a few times too

 

If it looks like that replace it, along with the coil wire.

 

Also do a compression check if that doesn't workout.

 

Ok I'll change out coil and do a compression test. What brand coil would u guys suggest?

 

Stock ac delco coil!
Compression Test:
Remove all plugs
Install gauge in plug hole
Prop throttle body open
Pull the injector fuses
Crank motor 3-5 revolutions each cyl. Write the numbers down for each.... hope you have good numbers across the board bro

 

I installed the new coil and now the check engine lights on and still runs like crap, my buddys bring over compressions tester tonight so well see how that goes.

 

just for the hell of it what is the gap on your plugs? My mechanic changed my plugs and set the gap at 50 and I had really bad misfire.

 

Think like 44 or somethin I forget I know I went by wat the chilton said tho. I just spent 3 hours pullin em all out for the compression test that I'll do tomorow, ill re check there gaps before puttin em bak n.. That's if it passes the test.

 

I did compression test all cylinders but 4 and 6 are at 170 and 4 is at 158 and 6 is at 145 Im pretty sure that means I'm screwed , wat do u guys think?

 

Did you do it Hot or cold?