Engine speed while shifting

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Jul 30, 2000 | 10:26 AM

keence

Thread Starter

Freshman User

Joined: Jul 2000

Posts: 31

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Engine speed while shifting

1992 Ford F-150 302 EFI with 5 spd OD. When I upshift the engine idle takes too long to come down. It does this in all gears. Scanned for codes and all comes back clean (11,11). Took the "Throttle Bypase Valve?" off and it had very little carbon buildup, cleaned it anyway with some brake cleaner and reinstalled. This had no effect. Engine still takes too long to come down. You can rev the engine at see the same effect. Do you think this valve is still the likely culprit? Base timing is correctly set at 10btdc.

New parts:
Plugs w/wires
Dist. cap and bug
PCV
Knock Sensor - It was tough!
Air Filter
Fuel Filter - Not changed yet, I must need a tool to get the lines off.

NOTE: I had a ping I couldn't get rid of even after all the new parts, I read an article about plug wire routing. I re-routed and ping was gone.

Thank you for your input.

Jul 31, 2000 | 12:51 PM

RGAZ

Senior User

Joined: Aug 1999

Posts: 343

Likes: 0

Engine speed while shifting

Sounds familiar. My truck doesn't come down when I shift either. It got better when I reset the computer, but now I don't have a cold idle (she starts and dies). I am sure I need a tune-up, but the rpm overshoot I attribute to either a bad TPS, bad kick-back dashpot or engine temp sensor. When I get around to the tune-up I will check them.

Basically, your problem (and mine) revolves around the computer getting the wrong information. I just got to find where the bad info is coming from.

Later.
Randy
88 F150 302 5 speed 4X4