solocus

I have a 87 L98 TPI Camaro that has an annoying misfire. Its not so bad at idle until the car in put into gear and then the engine vibration increases. Driving it misses under load (and probably when not under load). It feels kind of like one cylinder is not firing.

This problem arose after car sat for 2.5 years with the car not being started the entire time (yep, I should know better). It did fire up and run with the old gas but ran very bad until I ran all the gas through the engine (Probably another mistake here). Since, I have ran at least two tanks of gas through the engine and it has improved. I also tried some fuel injection cleaner in the tank. Maybe some very minor improvement, but maybe not. I did change the plugs, wires, cap and rotor. Still no improvement. I changed the fuel filter as well with no improvement.

I have checked for spark at the plugs and it is there. I put a noid on each fuel injector connector and the signal seemed to pulse fine.

I tried listening to each injector with a hose, but it was hard to tell if they were actuating. When touching them they all felt like they were actuating.

I pulled a plug wire off the cap one at a time to see if I could isolate a bad cylinder but pulling any plug wire made almost no difference, the car ran equally well with each wire pulled.

I'm still thinking its the fuel injectors, maybe working but varnished up from sitting. Would a fuel pressure regulator cause this? How about a MAF? Any ideas of help is appreciated.

Tuned Performance

iTrader: (92)

My bets on the varnished injectors

ploegi

Need to disable IAC to do cylinder power balance test. (pulling plug wires.) Otherwise, IAC just opens up a bit to raise RPM back to where the ECM thinks it should be.

GTA1990

iTrader: (1)

Poss. blocked evap canister (worth checking before looking at the more expensive stuff). If you have a non-vented gas cap, loosen this and see how it runs

solocus

You win! Some SouthBay injectors and she runs great. I only wish they were black instead of yellow since everything under the hood is original and I like to keep the factory look.