GREENC493

My car is a 93 lt1. About a year and a half I replaced the opti with a MSD unit, blaster coil, 8.5mm wires and Denso iridium plugs (the original opti would cut out and back fire: however, it would run ok and ocasionally it would get and go). The first few months I was happy with the new set up and then something happened, mileage and performance dropped off. I started locking for possible problems. I have been dealing with ignition troubles for weeks. The car has a miss at idle that I can here and if the air is on you can feel it. I have checked grounds, ICM, coil, wires and plugs. Still have a miss. The tech at MSD said it would through a code or not run if it was the distributor. I told him my original dis did not set a code and it would run, this seemed to make him mad (no help). So, the problems that I have are: wire arcing, miss at multiple cylinders(random), poor economy and lack of power. I have tried switching out ignition componets except the dis for obvious reasons. Does this sound like it would be a problem with the distributor or maybe the computer?

jimg's'93

You mention codes, but have you actually checked for codes yet?

0Paul Ruggeri

Could be an injector issue.

GREENC493

I got a 12 and a 32. I cleared the code before and it will stay gone for months most time. The 32 code is a EGR and the valve moves freely with no leak at the gasket. I pulled the intake over winter replaced the gasket which fixed my oil leak at the back of the block. I was thinking the 32 was from the lower back pressure of the Borla cat back. The fuel pressure I was getting at Idle was 34psi and with the vacum off it is 42-43psi. Drove the car with FPR vac disconnected and had the same miss: however, the car would get better cruising mileage(about 24mpg at a seady 60mph).

airplane50

You mentioned a Borla Exhaust. Do you have any other mods? Also do you have a factory service manual? There is a procedure for checking the ignition system as well as the PCM and fuel system. Stay after the misfire and preformance issues. Don't get discouraged. You will sort them out.

aminnich

Couple of simple, primitive, and free things to do:
1. Start it up in a dark place and look for arcing plug wires.
2. Use a cheap heat gun and read the temp at the exhaust manifold for each cylinder.
3. What were we talking about again?