Why does my pickup sputter when I shut it off?

[nans31]

This is the 1985 Ford F-150. It just started when I had spark plugs changed, rotor replaced etc. When I ask this question around home, I get the answer "it's a Ford". What's the REAL reason? It's kinda ridiculous sometimes, bounces around for a few seconds, sometimes seems like forever!
nan

[farminghandyman]

Originally Posted by nans31

This is the 1985 Ford F-150. It just started when I had spark plugs changed, rotor replaced etc. When I ask this question around home, I get the answer "it's a Ford". What's the REAL reason? It's kinda ridiculous sometimes, bounces around for a few seconds, sometimes seems like forever!
nan

IT's a ford, actually it is a common problem on Ford,
they have a solenoid on the carburetor that is to close off the butterfly plate and stop the air and kill the motor and keep it from dieseling, and some times that can come out of adjustment,

but that was a band-aid approach to the problem,

and that is either there is carbon or sharp points of metal in the heads that are glowing red and keep then motor running after the spark-plugs are no longer sparking, there is carbon build up most likely in the heads of a few cylinders, and there is little one can do, (I have heard of seafaom head cleaner can help),

[celticfalcon]

its possible the timming is off too.if you had a tune-up, plugs,wires,cap and roter, the distrubitor got turned a skosh.

[caballoviejo]

Originally Posted by farminghandyman

IT's a ford, actually it is a common problem on Ford,
they have a solenoid on the carburetor that is to close off the butterfly plate and stop the air and kill the motor and keep it from dieseling, and some times that can come out of adjustment,

but that was a band-aid approach to the problem,

and that is either there is carbon or sharp points of metal in the heads that are glowing red and keep then motor running after the spark-plugs are no longer sparking, there is carbon build up most likely in the heads of a few cylinders, and there is little one can do, (I have heard of seafaom head cleaner can help),

Years ago the story was that you could get rid of carbon build up in cyclinder head by pouring transmission fuid down the carb while you kept the motor revved up. I tried it once. Made worlds of white smoke out the exhaust. Don't know if it worked - never pulled the head. Did'nt hurt though. The vehicle went probably anohter hundred thousand miles.

[Beeman]

I ASSume this is a carb and not fuel injection in an 85 f-150. If the idle is too high it can cause this problem. The timing is another especially if it was adjusted during the tune up. If you don't want it to keep running when you shut it off just leave it in drive when you shut it off if it's an automatic. On a stick just stall it out with the clutch with the shifter in gear. That's a temp solution until you get it fixed.
Trans fluid will definetly clean carbon out of an engine when run through the intake, but it can also break loose a piece that can cause a problem. Seafoam lubricant is an excellent product to remove carbon, available at NAPA. Trans fluid will also clean sludge from an engine if poured in with the oil and run and then drained. Trans fluid will also clean your hands if you have heavy grease on them.

[nans31]

Different opinions here, I think. :haha: Carbon buildup possibly, and/or distributor cap got turned?? Putting something through the engine that may cause problems later doesn't sound good to me. Is this something I need to take it to the mechanic for? Is the seafoam something that goes in with the oil? I'm taking it in for an oil change in the next day or two, can they put something in then?
Nan.

[Beeman]

Sorry, we got off of your problem and on to something else with the trans fluid and Seafoam.
The carbon might be a problem, but if this just happened after the tuneup I would say it's probably tuneup related. From your post it sounds like you had someone tuneup your truck for you. If the problem occurred right afterr they worked on it I would bring it to their attention and they should take care of it for you. If it did happen right after tuneup I would say it's most likely due to them making a timing or idle adjustment.
For possible carbon buildup you could use Seafoam and add it to your tank of gas. it will go through the system and help clean off any carbon that might be in there.
I wouldn't add anything to the oil on your oil change, that was just a little off topic discussion.

[moopups]

Give it a dose of premium fuel and take it for a long hard run, such as an hour at turnpike speeds, this may help exit the carbon.