Need a little 22r help

[60chevy]

A friend of mine bouhgt an 86 pickup with a rod knocking in the engine, but he has an older 22r sitting around, how old you ask, I don't know. I do know that it was carberated. So we pull the FIed engine out and swap over all the stuff onto the older 22r put it in the truck, sounds easy huh. Low and behold the thing starts and runs pretty good. He drives it into town and on the way it starts running bad, rough and idles bad. Gets it home and we change the fuel filter. It runs great and life is good. Gets part way into town and the same thing happens. Drags it home, we drop the fuel tank, it looks good. Change the filter again, runs good gets part way into town same thing. Change the fuel pump and pressure regulater, not the fuel filter, no change dosen't even run good for a short time. Any of you 22r gurus got any helpful hints I can pass on to him. Other than stop driving to town. Thanks for any help.

[60chevy]

I guess the question was too hard.

[Erick]

It could be the Carburator. Sometimes it 's difficult to distinguish between fuel and ignition. These are computer controled carbs. I had something simular on another truck. It almost acts like an ignitor, has a little lean misfire, but you'd swear it was fuel. I know it wasn't the ignitor.

I know EFI better than those carbs. Grab another used one out of a boneyard. It would be cheaper than having it diagosed by a pro.