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I have a 1985 ford f150 p/u 5.8lt 4brrl that runs real good cold but runs real bad warmed up? Answered

it runs great cold but when it warms up it stalls  is hard restart it has a new carb  it has a new ign,
. plugs wires cap and rotor. System dosent overheat



Have you checked the fuel pump or filter? It takes 3 things for combustion. Spark, Air, Fuel. If your getting spark and air that means something is wrong with the fuel delivery. It could be the choke as vyger suggested but I have limited experance with that so can't expand on it.


6 years ago

So, its heat related it appears. My first choice would have been the choke, but since you replaced the carb ---- . Does it have one of those chokes that gets heated by the antifreeze? I don't know if you know what I am talking about but some models had this heater hose connection that ran water from the block through the choke. This way when the coolant got warm it would open the choke up. If yours has that then check it to make sure that the water is flowing and in the right direction. Also sometimes when the coolant gets low those are the first things that start getting a limited flow.
If that is not it then it has to be some other component that is heat dependent. They used to put a sort of butterfly valve in the exhaust to recirculate the hot exhaust until the engine got warm. Check for that and see if its working correctly if its there.
Well there is a start at least.