89 Trans Am Service Engine soon light flickers

1989 PONTIAC TRANS AM
69,000 MILES • 5.7L • V8 • RWD • AUTOMATIC
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CHEFTAYLOR69
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Hello, I have a 89 pontiac trans am 350 TPI stock and the service engine soon light flickers during acceleration. It does not stay on and there are no codes reading just 12. I have changed the spark plugs, wires, new air filter, and pcv valve so far. Runs great almost all the time, but has this one little issue that around 30 or 35 mph the light flickers, I think there is a slight, hardly noticeable fluctuation in power, then everything is great, light off and running great. This does not happen all the time, just once in a while and making me nuts trying to figure this out. Any help would be greatly appreciated. Thanks so much.
Jerry
Mar 11, 2014 at 5:44 PM
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HMAC300
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check coil wire for corrosion or being broken also have it scanned if there is someone with a scanner fo that old of a car sothey can see if there is an intermittent. check fuel pressure shold be41-47 psi. autoparts rent gauge.
Mar 12, 2014 at 6:56 AM
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CHEFTAYLOR69
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Hello, I have checked the things you have mentioned above and it all seems to check out, 41 - 42 psi for fuel and the ignition coil looks good.

Do you think if I took it to GM that they could scan it and find what is happening, even without the check engine light being on? There are no codes showing with the paperclip method, I am just stumped.

Took it for a spin just a bit ago and it did the same thing took off normal, got to about 35 or 40 and flicker and a slight fluctuation in power then all normal. Got to store shut off, started right up and headed home and no issues at all. So it is intermittent, what ever this may be.

Thanks for any more information you may have on this problem, I will continue to try to figure it out, but I am a lost puppy when it comes to this type of problem.

Jerry
Mar 12, 2014 at 5:08 PM
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HMAC300
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any garage should be able to scan it
Mar 13, 2014 at 6:54 AM