i have 87 bronco 2 that will not go up a long hill without starting to backfire and lose power. it runs like new around town . it also seems to crap out after a long drive or very hard exceleration. i have had it scoped on a machine for defective sensors but nothing shows up. i changed dist cap . plug wires. rotar.the fuel pump on the frame and in the tank and almost every sensor we can think of. the stange thing is that it will run like new around the city. unless you reallyput the pedal down hard for a long period of time. we have spent a lot of time and money triying to figure this out. it seemed to have helped a bit by changeing the dist cap and rotar .but will not make it up along hill . could it be a coil problem . i sure would apreciate any input. thank u.

 

Its a long shot, but have you checked the catalytic converter? It could be partially plugged.

 

dodgy fuel filter my friend ive seen it before and if ya replaced it, it could be around the wrong way good luck digger

 

Test the MAP sensor

 

It sounds like its loading up with gas.

I would look at the FPR.

later,
Dustin