Lopes no codes on obd 1 ?

1995 CHEVROLET SUBURBAN
150,000 MILES • 5.7L • AUTOMATIC
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BILL2934
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Chevrolet 350 engine lopes no codes on obd 1
I have replaced ignition control, module, and pick up coil. Got fairly new spark plugs and wires cap rotor button new injectors, new pressure, regulator valve fuel, pressure test, good timing checked and reset to 10° EGR valve seems to be good. Move up and down freely and hand new gasket All electrical connections appear to be good. I’m open for suggestions. I also have live data from my live scanner if I can share it on here I don’t know.
Jul 19, 2026 at 8:36 PM
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LONG TIME WRENCH
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Have you done a compression test on all your cylinders? That will tell you the condition of your engine is If all your cylinders are within the manufactures spec then you know your problem that your having isn't serious loping like almost going to die loping? Throttle body injected you checked for vacuum leaks? broken valve spring? If you havent done a compression check yet do that its quick and will give u peace of mind.
Jul 19, 2026 at 11:00 PM
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BILL2934
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OK, I will do a compression test tomorrow after work and I’ll send you a reply of the numbers. Thank you.
Jul 20, 2026 at 12:14 AM
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STRAILER
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I would look at the EGR valve as well. If it is leaking internally it will cause this issue. Here are 2 videos to help you with the compression test and the EGR test as well.

https://www.youtube.com/watch?v=KOxIm1F8AW0

EGR test

https://www.youtube.com/watch?v=DqUCbbKdWf4&t=1s&pp=0gcJCZkLAYcqIYzv

Please go over these guides and get back to me.

Jul 20, 2026 at 3:00 PM
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