Have done tons to my (not '96 as previously stated) 1992 F150 w/ 4.9 and e4od trans w/ 161 k.
I bought it with this issue and every 3 to 5 months they crap out.
I'd like to hear your theories.
Thanks.
Will

 

Other than suggesting to use a motorcraft part, check the cowl panel weatherstripping that prevents water from dripping down between the windshield cowl and hood. I have heard of those failing and taking MAP sensors with them.

 

A 1996 F150 w/4.9L engine does not have a MAP sensor. It should have OBD-II which uses a MAF sensor to measure air flow.

 

It's a 1992. Sorry about the confusion.
W.