LT1-LT4 Modifications 1993-97 Gen II Small Block V8

Occational low end miss? Help...

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Old 08-10-2009, 10:30 AM
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Default Occational low end miss? Help...

Ok so its somewhat hard to explain exactly what the car is doing but when just cruising at maybe 35mph and you hit the throttle real quick and let off right away, just giving the throttle a quick blip on occation the car will not make the rpms it should but it just misses (if you wanna call it that). Its hard to explain like i said but its just like the car doesnt react how it should, it should pull up RPM and increase speed, but instead it misses and almost sounds like a backfire but not loud at all just a quiet miss...

Sorry for the bad description but i just can't think of any other way to describe it lol. It only does it when you just hit the gas quick for a second or two, if i stay in the throttle it will pull through RPM...

Car has 226/234 AI Cam kit, ignition system is newer GM opti, stock replacement coil, MSD Wires, and tr55's gapped at .035... Fuel system is 255lph BBK pump, stock lines, new GM FPR, 24# SVO's... Rockers were recently adjusted with the motor running technique...

Any ideas on what could cause this?

Thanks!!
Old 08-10-2009, 11:40 AM
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Is it an intake backfire? I still think either your rockers are off or your PRs are the wrong length. You have tried everything else. Thats exactly what my car was doing when the rocker broke. If I was off and on the gas real fast a few times the fuel would load up since the exhaust valve was not fully opening, causin the intake backfire.
Pull the plugs and see if one is darker then the rest.
Old 08-10-2009, 08:11 PM
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Thanks AC for the suggestions, i will check the plugs and rockers this week when i get a chance! Any other suggestions from anyone?
Old 08-10-2009, 08:19 PM
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An exhaust leak could cause air to hit the o2's and cause pops or backfires. Just throwing that out there. Most evident with crackling, popping while engine is decelerating during engine braking.
Old 08-10-2009, 08:36 PM
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I would check the mass air meter sometimes they can get dirty and cause this type of problem. Take it off and clean it carefully and reinstall and see if the problem goes away. I have had this happen with my car and I described it as a hiccup.



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