power failure

[tastroud]

I have a 79 F-150 w/ 351m. I have a problem i am trying to work out. The truck will start and run fine, but once the truck has been driven for 30-40 minutes, it will just loose power while driving down the road. It will restart and continue running at idle speed, but does not have the power to allow me to drive it. I can let it set for several hours, let the engine cool, and start it right up and drive it home. Initially i thought it was an alternator, or charging syatem problem, but i can test the battery, and the alternator, and they are working fine. Any suggestions?

Thanks
TASTROUD

[bob arrington]

fuel filter , a plugging cat, a controll module going bad,good luck,bob

[bigperm2]

it also could be a bad fuel pump or vapor lock. I have the same problem w/ my bronco, and I believe it is vapor lock. I am in the process of installing an electric pump!!
my $.02
-dan

[Torque1st]

Carb icing can do that also, but it is more likely that your ignition module has failed. You can get it tested at any good parts store.