Rough Idle when Hot
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Joined: Jan 2008
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Rough Idle when Hot OK so here's the deal, 1994 firebird 64kmiles. I purchased it with a Vortech on it and a broken #6 piston. Rebuilt it and stuffed it back into the car (with out the supercharger). So now its just a plain vanilla LT1 with Headers and no cat. Original problem from former owner is was that is was misfiring when hot thinking thats what popped the piston. Runs like a raped ape when cold (open loop) as soon as it gets to 160 or so, idle sucks and misfires on hard acceleration. Very bad under load (6th gear). So far I have replaced (shotgunned) optispark, plugs, wires, Ignition module, coil, and not one but both front tires.... Pulled off the hypertech programming and no change. Scan reveals no codes. Output from both O2's look good. FYI - engine was a full rebuild. Just talked to previous owner and he said thats exactly what he had before it blew last time. Any suggestions would help. Problem seams to be in closed loop only.
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Joined: Aug 2008
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wow i hope you find out, because i'm having the same exact problem *1994 formula m6, w/ long tubes and no cats*. I can drive my car around, but after it gets warm it goes into closed loop *like you had said*, it starts to miss and backfire like nothin else. I keep scanning it and it's showing probs with the TPS and the MAF sensors, and both of those check out fine, but today i'm going to check everything with the ignition and fuel, and i'm hoping that's what it is, cuz it's gonna suck if my engine ends up blowing something
*i've replaced plug wires, plugs, checked coil module and alternator and i was hoping it wouldn't be the optispark*
*i've replaced plug wires, plugs, checked coil module and alternator and i was hoping it wouldn't be the optispark*
