My car was misfiring...or missing when it warmed up.....didnt do it while at idle, but only under load. I replaced the icm and the coil, thinking this would fix the problem. Tonight I went for a ride and after 10 highway miles, at 1700rpm, it missed....I cruised home through the city and the car runs strong at higher rpm. It is strange...I have a B&M Ripper shifter so I feel how my car is running throuh it. Sometimes it is sooooo smooth...at times it is a bit shakey. Not sure what to think anymore. I know its not a tuning issue because my plugs are clean and my wires are tailors 8.5mm running on my valve covers. All conctions are tight. Should I be looking at Delteq? I am running out of crap to replace.....it seems like an electrical issue, not a mechanical issue

 

A 58 mm TB is not recommended for anything less than a 383. Unless you have a tune for speed density, modifying the MAF is not recommended either, although I did not see anything in your sig about it.

If it only does it under load, see if you can create the miss parked by letting the clutch out a little with the brake on. If you can do it then, check to see what the fuel pressure is doing at that point. If it appears normal, check the wires with an inductive timing light to see if any are misfiring.

It may also be worthwhile to view the injector pulse width and short term fuel trim.

 

its not the tb. The missfire began last year. The ar is a 94 and has 28k. should I replace opti or go with delteq?

 

Why would a distributor cause a problem with mid range rpms but not low or high? Remember, there are 2 sections. Feedback signals from the optical encoders and the high voltage side of the cap and rotor combination. If you suspect a problem with either side, a scope can be used to view them. If they were the problem, the scope could point it out at idle.

The funny thing about your problem is that on Dream Car Garage, they had the same problem on a 4th generation Corvette that they had earlier replaced the injectors with 24# units. They changed the injectors to 21# units and eliminated the problem.

 

the issue i at low mid rpm...like the car misses then regains power. I am coming to the conclusion that the opti is arching or something.