Ford Repair: 1989 F150 4.9Y, pickup coil, correct fuel

Question
If the outside temp is cold I can drive the truck as much as I want with no problems.  As soon as the outside temp reaches 70 and above I can drive a short distance and then the truck will die out.  Almost like it is a fuel problem but I did a pressure test on the fuel system and it passed.  I put a new high pressure fuel pump in, coolant sensor, act sensor, tune up.  I did a scan but received no codes from the computer.  Your help is appreciated.

Answer
sounds like you have thrown/wasted a lot of money on this problem and i hesitate to give you any possibilities because whatever i say may cause it i am afraid instead of having it checked you will just run and buy a cheap part and put on it-and after your problem is actually found and repaired your truck will be full of cheap parts in other areas that are now worse that what was on it to begin with-hope your not buying cheap parts but after 30 years of this thats what i see most-now to your problem-please have it checked

when it dies out do you have spark at the plugs-you say you have correct fuel pressure but what about volume although rare you can have pressure and not enough volume-ignition module-pickup coil in distributor and or ignition coil can cause this also.

you may actually save money by having it checked out.

good luck.