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Random RPM Drop

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Old 11-07-2012, 09:18 PM
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Car: 90 Camaro
Engine: 305 TBI
Transmission: 5 speed
Axle/Gears: 3.42 POSI
Random RPM Drop

My car idles normal when its cold but when its warmed up it randomly drops then surges. It also idles faster when its warmed up. I have an ebl and and there is no tps reading until it drops. I have been told that it could be vacuum but when spraying a flammable substance by all the spots that might have a leak nothing changed.
Old 12-12-2012, 06:46 PM
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Car: 90 Camaro
Engine: 305 TBI
Transmission: 5 speed
Axle/Gears: 3.42 POSI
Re: Random RPM Drop

UPDATE:
Replaced all vacuum hoses and no change with the rpm drop. Replaced top injector pod gasket and now it will die.(Until I changed rpm stall saver in EBL)
Before and after replacing the gasket i had another problem occur. Will driving down the highway I had it randomly surge backfire and decel several times before returning to steady rpms. It will now severely backfire at high rpms under load. Any ideas?
Old 12-12-2012, 07:01 PM
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Car: 1984 Z28
Engine: L31
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Axle/Gears: 10 bolt 3.73
Re: Random RPM Drop

sounds ignition related. double check your timing, plugs, wires, cap/rotor, ICM, etc...
check resistance cold and hot
also check fuel pressure for weak pressure at higher RPM
Old 12-12-2012, 08:08 PM
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Car: 87 trans am
Engine: 5.7
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Re: Random RPM Drop

have you recently done a tune up and maybe install the dist 180 out? Check your timing for sure and make sure its correct. also check your spark plug boots at the plug side and make sure there isn't any melting cracking or splitting.
Old 12-12-2012, 08:30 PM
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Car: 90 Camaro
Engine: 305 TBI
Transmission: 5 speed
Axle/Gears: 3.42 POSI
Re: Random RPM Drop

The distributor is correct. I believe all the plugs and wires are good I replaced the not to long ago but a couple months before the problem started. Thanks for the reply
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