RobotWizard

Just got a hold of a 1985 F150, straight 6 for $300. It's in rough shape but it runs alright so I'm gonna do a little work on it. Main problem I'm having is just a rough idle on cold start (not cold weather related). It sputters and coughs and kills. If I lay on it until it warms up then it runs fine.

I'm assuming maybe a carb adjustment will do it. Problem is, although I do turn some wrenches, I only know enough to be dangerous.

Any suggestions? Thanks in advance.

EDIT: Already put on new plugs, wires, distributor cap and rotor.

J

Good old Bill

"although I do turn some wrenches, I only know enough to be dangerous".

So, what makes you different than the rest of us? Have a question or two, is this still a carburator or is it fuel injected? Hoping its a carb with the choke plate closed and restricting air flow.

RobotWizard

Ha, good to know I'm among my own kind!

It is a carburetor and I'm 99% sure the choke plates not sticking....although I'm in there with my foot on the pedal to keep her going so I'll have to check to make sure.

More info: Once it gets nearly warmed up enough to run steady I'll take my foot of the gas and it will idle rough until it's just about to kill and then the the idle will kick up and rev the engine. Then it will back off again until it's nearly dead, then rev again, etc. It does make me think that's somethings just sticking...

brns fan

I am having the same problem, did you figure out what was causing yours?

tsumrall

Not sure this is the fix but it helps. Try increasing the idle a bit. Should be a large screw behind and left of the main linkage.

Does she run rich? Smell gas at the tail pipe?

ecoguard

lol i used to have that with my 76 4.9 i started to adjust the controls on the carburetor, i managed to fine tune it to the point it was burning water and it ran smooth
i also emptied a can of carb cleaner into it lol