back firing through TBI and transmission not shifting out of first gear while driving

1995 CHEVROLET SUBURBAN
380,000 MILES • 7.4L • V8 • 4WD • AUTOMATIC
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JOE1194
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  • 1 POST
i have replaced plugs wires cap rotor shift solenoids and wires in transmission, ECM new, fuel filter new, injectors, new fuel pump, and it still will not shift out of first when going down the road. it falls on its face off the line and backfires through the tbi only on the passenger side of the tbi. it didn't do it every time i drove it until just recently.. oh, and the TPS has also been replaced. please help, and thank you.
Mar 15, 2021 at 12:12 AM
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ASEMASTER6371
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Good morning,

I would start with a compression test. Backfiring is usually from a timing issue or a possible valve issue.

https://www.2carpros.com/articles/engine-backfires-while-running

https://www.2carpros.com/articles/how-to-test-engine-compression

If the compression is good, take off the valve cover and watch the valve movement while running to be sure all the valves are moving the same distance. They had issues with the camshafts wearing down and the valve movement being effected.

Roy

Mar 15, 2021 at 2:15 AM