ive got a 93 f150, 4.9 I6, standard. my problem is when i cold start it, it will cranck right up but when i try to start it after its at runnin temp, it acts like its missing on a cylinder, sometimes it will fix itself if im idleing at a light. ive checked all the plugs and wires, cap and rotor, replaced them about a year ago, any one have any ideas on what it can be

 

4.9s used to have a reputation for hot re-start problems. The heat from the exhaust manifolds would percolate the fuel in the rail. At one time Ford installed a blower fan to cool the rail but on later models they just installed a heat shield over the exhaust manifolds. I'm 99% certain the 93 had the heat shields. Are yours still in place?

 

yea i see it there, ive had the truck for 2 years and its run fine. there is 1 wire that im questioning, when i pull it when the truck is running it dont seem to make a differance, but it is sparking i know that, ive changed that wire and plug, its still doin it

 

What's the fuel pressure? Get a Haynes manual & a digital multimeter, and follow the ignition diagnostic in Ch.5, usually Sec.5 or 7. Test compression & vaccum as described in this caption:

 

thanks for the input guys, but it was what everyone was telling me it wasnt, my coil, runs like a champ now

 

i have that same exact problem with my truck.i have a 1990 f150 with a5.0, runs fine for about 20 minutes, then starts to miss. everything is new, plugs, plugs wires, cap is in good shape.i already ran 2 cans of sea foam within a couple weeks.i dunno if it could be injectors they have never been replaced the only way id know is to hook it up to a pressure test right??

 

Are u saying it WAS your coil? On my 1991 300 inline six, it cranks up easily and is okay until the needle on the temp gauge just starts to enter the NORMAL range. Then it starts to buck. Have new plugs and wires, new distributor (pickup coil, ignition module, etc). Mechanic said fuel pressure was okay (maybe that was prior to warmup). Have given it the vacuum Seafom treatment and run a liberal amount thru the tank for the last 2 tankfuls. Do I maybe need a coil? Thanks, Jim M