misifre struggle
Thread Starter
2nd Gear
Joined: Oct 2023
Posts: 2
Likes: 0
misifre struggle
Hi, I really need help with this one, 3 mechanics have failed so far. 11 months ago my 95 c4 shut off while driving and the opti was replaced to have it run but have a horrible misfire. It then had multiple parts replaced listed below but only the leaking brake booster made it much better. It sometimes shuts off in gear but has full power e.g no bogging down when throttle applied. seems to run a little better when hot. I pulled the opti off and checked it was on right and it ran fine for 4 minutes then started going bad again (sometimes runs sweet for 2 minutes). Only thing I noticed was the opti wiring loom has a pin slightly bent back- it didn’t start for one mechanic until he played with it. It uses no coolant and no smoke so cant be heads really? No codes are given at all. The optispark was checked and had good wavelength? Plug wires tested and also good fuel pressure. The misfire is across all cylinders randomly
Parts replaced
- Optispark
- Spark plugs and gapped
- Coil pack and ICM
- TPS
- Mass airfow sensor
- Egr valve
- Fuel pressure regulator
- Cats deleted
- Idle air control valve
- Vapour canister purge valve
- Pvc valve
- Brake booster valve
What should I do from here?
Thanks
Parts replaced
- Optispark
- Spark plugs and gapped
- Coil pack and ICM
- TPS
- Mass airfow sensor
- Egr valve
- Fuel pressure regulator
- Cats deleted
- Idle air control valve
- Vapour canister purge valve
- Pvc valve
- Brake booster valve
What should I do from here?
Thanks
Melting Slicks
Joined: Apr 2001
Posts: 2,105
Likes: 220
From: Ca.
" Only thing I noticed was the opti wiring loom has a pin slightly bent back- it didn’t start for one mechanic until he played with it."
I think you answered yourself right there. If you have to splice in a new wiring loom to the opti-get it from a junkyard if you have to. Also any codes thrown?
I think you answered yourself right there. If you have to splice in a new wiring loom to the opti-get it from a junkyard if you have to. Also any codes thrown?
Melting Slicks
Joined: May 2003
Posts: 2,076
Likes: 281
From: Dyersburg TN
just from the info I am thinking injectors should be checked. I had a random miss and when I put Ohm meter on injectors 6 were perfect and 2 of them had a reading of below 4. It is so quick and easy to check. I didn't even get my hands dirty checking them.
Thread Starter
2nd Gear
Joined: Oct 2023
Posts: 2
Likes: 0
yeah ive ordered a new opti wire but dont have high hopes. no codes at all, the injectors have been checked and seals replaced. nearly new fuel filter as well. ill let you know how the wire goes when it arrives
