I own a '97 F150 with approx 48K mi on the motor. I noticed the engine is starting to idle after I drive it after an hour or so. I took it to the dealer but they told me they could not reproduce the symtom. When I had the oil changed and had the head mechanic look at it, he noticed it too and said it might be a bad cylinoid. I have no idea even where to start to troubleshoot this since the dealer gave me no help whatsoever.

 

What engine do you have?

Please be more specific about what your problem is. Is it a rough idle? Is it a miss that happens at various rpm ranges? Has your gas mileage gone down since it started this problem? Is it surging (i.e., rpm rises and falls on it's own).

Give us a bit more info.

 

I have a stock 4.6L V8 with a Flowmaster exhaust and 3" piping. The engine does have a rough idle when it is warmed up and driven for about 30 minutes. When I am on the highway it seems fine but you can tell that the motor isnt feeling like it is reaching its full power. I'm not sure about gas mileage since it is a V8 but it seems to be about right on that department. There also is a very light pinging sound when I accelerate up the hill to my work. It is hardly noticeable but still I have concerns about it.

 

It could be a bunch of things.

One possibility is your injectors are dirty. Your symptoms seem to point in this direction. You might want to run one of the better injector cleaners. I've had good luck with Chevron Techron. Not the fuel injection cleaner, but the full strength Techron. It might help clear up your pinging problem too. I haven't tried it, but members here swear by the treatment from Redline. I've had good luck with Techron, though.

Follow the directions on the Techron bottle. It comes in two sizes. The small one treats 10 gallons and the other 20. Should run you around $6 for the small bottle up to around $12 for the large one.

If that doesn't work, then I'd start looking at the plug wires. Might be about time to change them. I've also heard that even though the plugs are supposed to last 100,000 miles, chances are they won't.

I'm sure others will have more ideas for you.

You may want to use the search feature of this message board. Search for "rough idle" in this (engines) forum and you'll get a virtual encyclopedia of causes and fixes.

On final thing. Welcome to the board!