Ok, I own an 88 gxl, here's the prob when first turn on the car everything is fine but when the engine is warm
and in 1st gear the revs decrease to 750 then in a stop and gear is in neutral the revs decrease to 500 then jump to 900 or 1k then again to 500 it doesn't mantain idle speed until I push the accelerator a little bit before it decrease to 500 again to make it stop doing that then it stays at 600 or 700 rpms, another thing, it backfires and getting flames at 5 or 6k in neutral also in first when I shift to neutral, I'm not sure what's wrong any ideas could it be the tps,ecu, or what?

Thx
MAX