My 1993 F-150 5.0L 4X4 XLT auto has a small problem in that when the truck is warm and you shut it off for approx. 15 minutes then restart it, it runs rough and low RPM for a little while then clears up. If you start it up quicker than this then it doesn't do it and also if you let it sit longer it's OK as well. It blows no smoke during this time to indicate flooding and as a matter of fact the tailpipe is clean and it passes an E-test with no problem. There are no codes and truck runs well otherwise. Also fuel pressure is fine and does it on either tank. I have changed out nearly every sensor to no avail and several shops have also looked at it and cannot figure it out even with scanners connected to it. If anyone else has this problem figured out I'd love to hear about it.

Cleat

 

did you change temp sensor my 1990 Bronco 351w did that i took it to a shop and they said it was the temp sensor.

 

I did in fact try changing the temp sensor but it was a used one I put in. Maybe I should buy a new one.

Thanks, Cleat

 

I haven't worked with Fords for very long, but I have had the same problem on a couple of chevies with fuel lines being too close to the block or an exaust manifold. This will cause the fuel to expand and evaporate inside the fuel line, creating a kind of vapor lock. It showed up only after the engine had warmed up and been shut of for a bout 15 minutes. If it's restarted right away, the fuel doesn't have time to flash in the line and it starts fine and if it's completely cool, then it settles back to a totally liquid state. It really shows up with a weak fuel pump and a hot fuel injected engine. I don't know if this is even remotely related to your problem, but I thought I'd throw in my two cents. Good luck...