Engine stumbling HELP!

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Aug 30, 2021 | 05:56 PM

Blue Racer

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Engine stumbling HELP!

I have a 2000 Trans Am LQ4 engine, Tick polluter cam, Long tubes with 3" dual exhaust,Fast 102 intake, Nick Williams 102 TB, These were upgraded in order to find lost boost. The intake was not the problem. Aero Motive 340 pump, Aero Motive fuel pressure regulator, and a D1SC with 10 lbs of boost. It will crank and idle but stumbles bad and misses when slowly giving it gas up to 2000 rpm if i mash the gas fast it will rev. I have installed new NGK BR7EF plugs gapped at .030. New AC Delco plug wires. New AC Delco 02 Sensors, New car quest crank sensor. I have changed out the IAC and the TPS with ones that I had on my 2000 Silverado that are working fine. They are the same part # also.Fuel pressure 58 PSI. I also change out the ECM with the first one that was in the car. The engine and build has less than 500 miles. Compression check is good. Could it be a ground or the cam position sensor? Also it was running strong until I broke a blower belt.
Thanks!

Aug 30, 2021 | 08:42 PM

eTXOne

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Do you still have a MAF? If so you may try unplugging it while running and see if it runs better when unplugged.

Aug 30, 2021 | 09:35 PM

Blue Racer

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Quote:

Originally Posted by eTXOne

Do you still have a MAF? If so you may try unplugging it while running and see if it runs better when unplugged.

sorry I forgot to tell you that I have a speed density tune. So I no longer have the mass airflow

Aug 31, 2021 | 04:16 PM

Old Buzzard

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From: Bostwick, GA.

There's a forum for help with this type of issue[s].

Aug 31, 2021 | 05:52 PM

IGN-1A

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Lean missfire OR Black smoke ?

When at 2000 RPM, do you see "black smoke" in the exhaust tips OR the sent of high HC ?

Aug 31, 2021 | 10:31 PM

Blue Racer

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I'm not seeing black smoke. Not sure what HC is?

Aug 31, 2021 | 10:59 PM

IGN-1A

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HC = Hydro Carbons

Hi, Hydro Carbons are unburned fuel created when the engine is too lean, a strong sent and this gas will also "burn" your eyes.

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Sep 1, 2021 | 11:54 AM

Blue Racer

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I agree but I have no experience doing this? Anyone close to Lexington NC that can help?

Sep 9, 2021 | 08:32 AM

#10

gagliano7

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From: Monroe,NY

I had a similar problem once and one of my injectors was dumping to much fuel at idle but when i revved mis went away.Not saying that is your problem but something to look at. I found the injector by pulling rail and putting 58 psi on it and found the injector that was leaking down.