I have an 87 f150 and it has a rebuilt motor. It will randomly die and won't idle at a steady rpm and has no power when I floor the gas. About the only thing that I haven't replaced is the computer. Would getting a rebuilt computer fix this? And is there anyway to tell if the computer I have is original to my truck?

 

Have you checked for codes?

Yes you can check to see if you have the correct computer by cross referencing the part number on it with the calibration code listed on the door jamb (aka B pillar) at Motorcraft Service dot com.