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Nov 9, 2018 | 12:03 AM

Ls1life

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Ls1

I have a freshly rebuilt 5.7ltr ls1 under acceleration I randomly have what sounds like a misfire between 3-5k rpm. I’ve put on a scan tool and it says all my coils are sparking and my plugs look good and are new, I have a vx ss it’s also cammed and has had a tune previously to the rebuild. Any help please guys I’m sick of pouring money into it....

Nov 9, 2018 | 11:54 AM

jetech

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From: Dade City, Fl.

Possible dirty injectors.? Any "changes" to the engine when the rebuild was done? Displacement, headers,intake,TB,etc.?

Nov 9, 2018 | 12:21 PM

SouthernRex

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My car started misfiring bad from a dirty MAF. Don't know if that helps you, but cleaning that helped me a lot.

Nov 9, 2018 | 10:53 PM

bammax

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From: Winter Haven FL

Dirty maf, lazy O2's, fuel pump straining to maintain pressure, bad tps, or a handful of other things. Start with cleaning the maf and checking fuel pressure under load since those are cheap to do.

Nov 10, 2018 | 05:26 AM

Ls1life

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Quote:

Originally Posted by bammax

Dirty maf, lazy O2's, fuel pump straining to maintain pressure, bad tps, or a handful of other things. Start with cleaning the maf and checking fuel pressure under load since those are cheap to do.

it’s had a maff tune so there is no maff sensor, what is tps?

Nov 10, 2018 | 07:58 AM

FirstYrLS1Z

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From: Euclid,Ohio

TPS is throttle position sensor.