any ideas appreciated

[yellowcamaro]

hello fellow f-body people. I am a new member though i have viewed this forum off and on for years. I now need to see if anybody has advise. I have a 93 Z28 auto and just recently it has developed a high rpm problem. as it reaches the 5000 or so rpm mark it has a strong miss and occasional pop from exhaust. have noticed a flame with the pop. feels to be ignition to me. i know of the common opti-spark problems and replaced it wee over 50k miles ago. my thought is that it may be going out again. only problem i have seeing that is that they normally just go completley out. if anybody has seen this problem and has an idea please let me know.

thanks, Larry

[raroZ28]

I'd say it's the opti. Could just need a tune up though.

[TraceZ]

They dont normally go completely out. It is very common for optisparks to die a slow death. Chances are your opti is going out again.

Did you buy a brand new delco unit or a rebuild of some kind? Did you replace the entire opti, or just the cap and rotor? Was the part warrented?

[yellowcamaro]

i put a brand new complete gm unit on it when it went out the first time. and needing a tune up is unlikely, only 10k on plugs and wires. does have original coil though.

[Injuneer]

I'd check everything else first, before replacing the Opti. To get a flame out the exhaust, you have to be dumping raw fuel into it. A misfire would do that. Cross-firing on the wires would explain it, for example. Could be anything from plugs, wires, coil, IC module, harness connections, corroded wire terminals, weak engine/computer grounds, and yes, maybe even the Opti. But I wouldn't jump to the expensive fix until I had ruled out the cheapeer ones.

Do you have an SES light on? Have you scanned it (short the ALDL with paper clip on your 93) for codes that don't turn on the SES light?