Hey guys, so I just recently purchased a 1986 F150 2wd with the 4.9l 300 straight 6 and 4- speed manual transmission. I'm hoping someone can help me get the issues it has smoothed out, or at least point me to a smaller list so I don't begin chasing things and replacing parts unnecessarily. Basically, the truck runs like an absolute sewing machine, smooth as silk, until it doesn't. It always fires right up on cold start and runs great. After several minutes of running, it starts running VERY rich, smoking, and barely clings to life at idle, and oftentimes ends up dying if you don't nurse the throttle. Even then, many times I can shut it off, wait a couple of minutes and fire it back up, and it smooths back out, no smoke, no rich gas smell or anything, but eventually the issue comes back. Sometimes it runs great and idles smoothly until you shut it off, other times as soon as it gets to operating temperature it bogs down and runs terribly. It also always takes throttle and acceleration well, and as long as your cruising down the road you'd never know much of an issue. However, as soon as you come to a stop sign the problems start and usually it'll die. Any help is greatly appreciated! Thanks everyone!

 

That is how it always goes, "works great till it dose not"

How long have you had the truck?
Has it sat around for a long time?
Did this start over time or all at once?
Anything done just before this happened?

One of the things you need to do is pull codes to see what the computer has to say is wrong as a start.
Dave ----