Off idle stumble - help??
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Off idle stumble - help??
Hey fellow FTE members, a newbie myself. Just picked up a '93 F150, 4.9L six, auto tranny, 2wd, etc. Has 137k on the clock and stumbles off idle. For example: as soon as i stop (in drive) and accelerate away the big 300 chokes a bit (amosts dies but doesn't. I haven't tried to punch it but I would think it would die. Any suggestions where to start? 300 runs super strong and have no other complaints, shifts great, only an occasional rough idle. Could the stumble be too much fuel off idle? O2 sensor? vaccum leak? I know alot about air and water cooled vw's but just started with the ford 300. Any suggestions, comments, etc. would be great. This truck rocks - fu** the compacts I have had before!
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From: Lewistown, PA
If you just bought it, I would replace the plugs, wires, cap, and rotor. Check for vacum leaks by spraying carb cleaner or ether on a vacum line. If there is leak, the engine will pick up speed(rpm) as it burns the carb cleaner. Aslo, check and make sure that your timing is correct.
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From: Hitchcock, TX
Originally Posted by 77300i6
If you just bought it, I would replace the plugs, wires, cap, and rotor. Check for vacum leaks by spraying carb cleaner or ether on a vacum line. If there is leak, the engine will pick up speed(rpm) as it burns the carb cleaner. Aslo, check and make sure that your timing is correct.
I just bought a '90 F150 300 6 w a 5spd. manual (been lookin for that set up for 6 mo.) anyway I had a similar problem initial rough idle at startup and occassional hesitation on mild acceleration. So the first thing I start thinking is O2 sensor or injector. Talked to a friend familiar w Fords and he said the same thing as 77300i6, check the dist. cap, rotor and plugs first . I usually start thinking high tech big buck solutions I never think of spark plugs and rotors - didn't they go out w carbs?
Last edited by eclecticcowboy; Mar 30, 2005 at 04:36 PM.
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From: Lewistown, PA
That very may well be an ignition problem. My wife's car ('91 GM) has the coil packs as opposed to the old distributor setup. One day it started running like most GM's do. When It was cold, it ran fine, but as it warmed up it ran like crap. I was thinking it was sensor going bad. I replaced the plugs and wires a few weeks prior, so I knew that they were fine. When I checked out the coils, I found one to be bad (orange-red spark as opppsed to blue). I replaced that and it runs great, as far as GM's do.
