Okay so I bought my car in May.
its a 97 z28 with 51k miles. Minor upgrades to the engine, major suspension work, major stereo work. It has been not giving me any problems at all, until a few weeks ago. I broke my transmission mount a few months or so ago, so i was taking it easy on my car, but i got it fixed last month... wanted to get into it. Im getting major hesitation/missing about 4500 rpms. Nothing really happens.. just seems really jumpy and rough... but no other signs to point me toward whats wrong. I have been noticing a build up of black on the back bumper by the tips inbetween washes.

Now im thinking optispark which i want to change anyway, but maybe something else? Any ideas? I'm not exactly extremely good at working on cars, but i have friends who are. We are planning on ripping to opti and water pump off in the winter while the car will be sitting. Any input on where i should start? All my mods are listed on my carspace page in the link in my sig. Thanks!

 

Is the SES light on?

 

Check this page out.

http://www.f-body.org/oldfaq/html/faq/index.html

Go about 1/3 way down the page and it has some info on the opti misfire as well as some other things that could be causing a misfire. It's also got a bunch of other good info.

 

No ses light. No lights at all.
Thanks for the link I'll check it out!