I have an 86 ford ranger with the 4d55. It starts and idles great. no smoke, no funny sounds. if not moving it revs freely and builds to about 10-12 psi boost.

On the road it seems to have no power. It can barely get above 45 mph. I'm thinking it could be a constriction in the fuel pipe, the ford has an electric feed pump that could be dead, or it could be the timing is off?

Any ideas?