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Hey, my 89 F250 7.5l has a weird issue. I'm not too familiar with this old school F/Inj so bear with me. starts fine (cold anyway), idles down to normal 650ish, put it in gear, D or R and it revs to like 1000 rpm and tries to drive away. Put in N or P goes back to normal 650 rpm idle after almost stalling. Sometimes it does stall. Seems like in gear there is a vacuum leak.
Any ideas?
Does it shift hard also? Check your engine trouble codes first. Even if you don't have a CHECK ENGINE light, you may have several active codes.
If you don't have any codes, I'd look closely at your Throttle position sensor (TPS). They wear out and create dead zones in the throttle sweep. This dead zone is seen by the ECU as the Idle position. When it's at real idle, the ECU sees it as being above idle and increases your timing.
It’s a connector under the hood you need a special obd1 scanner or a paper clip.
https://youtu.be/-YYQKssOEOs?si=CJwdUmAUnv54DwZ-
think this is the video I watched
You can still get codes without a CEL. Look up ford OBD1 KOER test to if you can get it to run to temp.