Okay, I've got a 93 Camaro Z28 M6 and the only mods I HAVEN'T DONE is a power adder and the shortblock. I'm running a Delteq DIS, among other things. I'm having a engine stumbling problem though, between 2000 and 2500 RPMs. My car idles perfectly (for a cammed engine) it accelerates without any problem, but if I hold the RPMs steady between 2000 and 2500 RPM, the engine speed will erratically dip down about 500 RPM. This isn't consistent, either. It has happened when the engine was cold, but also when it was hot. The thing is too, it only happens randomly, and it can last for a few minutes, or as long as 30 minutes or more. My only guesses are either a bad coil on my Delteq, a bad optical sensor on the distributor, or faulty plugs. I'm hoping it's the plugs because they're the cheapest fix. Right now, I'm running some junk Bosch plugs, and I've got some NGK TR-55's that I'll be throwing in there this week. I'll let you guys know if that fixes it, but until then, could anyone else give me some ideas as to where my problem could be? My car ran fine until I got it back from a local shop. It hasn't been the same since...

 

bump, anyone have some suggestions here?

 

Okay, just to give you an update, I may have found the problem...

I'm not sure if this would cause my problems mentioned above, but I was changing my spark plugs today, and found that my K&N air filter cone (from my CAI Kit) was GONE!!!!! Damn friggin' mechanic LOST my air filter, and I've been driving it around, for who knows how long, like that!!!! This is most certainly the last time I get lazy and let a shop do something I know I can do on my own. I've already ordered a new filter, and I'll have it tomorrow, so I'll let you know whether it solves my hesitation problems...