Ok I have a 1986 f150 300 inline 6, 4 speed 4x2. A few months ago the truck started running bad it was stalling on deceleration. Spitting and sputtering on acceleration, having trouble idling (sometimes idled high and sometime idled low) most of the time it would idle low. We did a tune up. Plugs, wires, cap, rotor, oil change. Truck still ran about the same. Tried to rebuild the carburetor and ended up just replacing it. Put it on and the truck was running very high idle like 2000 rpm or more(tach is broken) and the exhaust was glowing red. Shut it off and it backfired through the exhaust very loud and blew off the lower radiator hose. Reattached the hose filled the radiator. Figured it had a vacuum leak so I plugged all the vacuum hoses on the truck. Rechecked the timing it was good. Now the truck starts and the exhaust is glowing but not at the header. Just the pipe. And it backfires through the carb. Any ideas? Sorry for the long post I'm just trying to give all the info.

 

Do you still have a cat converter? If so it may be plugged.

 

No the converter is gone.

 

Welcome to the forum, Will Goolsby!

Read this attached link and see if any of it sounds like your truck: https://www.ford-trucks.com/forums/1...expensive.html

 

Did you check the fuel pump? maybe unplug the fuel line and crank the starter... to see if fuel pours out of the unplugged line. That is a cheap and easy fix. Also change the fuel filter if you haven't. Hot exhaust manifold sounds like its running super lean.

 

Also if you didn't.... check the vacuum tree under the carb for broken vacuum caps

 

 

FYI the 86 300 should be a feed back system and the timing & fuel some what is controlled by a computer.
If anything is not right (sensor) or missing (cat) the system goes into a "limp type mode" and runs like crap.
He could use a test light to pull codes to see what the computer sees wrong.
Then again OP was 10 days ago and only 2 posts so may never know if he got it to run better or not.
Dave ----