the trans am has defeated me, after many hours off messing with the tpi system, Ive come to the conclusion it quite possibly could be my camshaft, I have no idea what make it is or the specs on it, but I do know at idle (timing right on, no vacuum leaks) I'm only pulling like 13-15 inches of vacuum, I readjusted the valve to no avail, still no improvement, keep in mind this is a speed density tpi system, its still running rich, and also surging very bad while accelerating, I did change plugs, new wires fuel filter the whole nine yards, with no improvement seen, can this low engine vacuum be the ultimate heart of my problems since the map sensor is seeing such a weak signal ? if so I have a painless harness for use with a mass air flow system, would I be better off switching to mass air flow since I do have this low engine vacuum problem, you probably have questions about whats in the motor so I will answer them the best I can, first off its a 78-84 305 thats been bored .30 over, flat top pistons, I am using the stock heads that came with my trans am (no porting or anything like that has been done to them, they were however milled just enough to to rid them of imperfections, machine shop told me they had no cracks or any signs of excessive warpage) I'm using new bosch 19#lbs injectors, compresion is 170-175 per hole, however as I said before the guy that built the shortblock didn't know what the cam was.
so whats your opinion switch to mass air flow, Im not really to thrilled about changing the cam and will mass air flow be able to not depend on any vacuum signal, I really dont know much about how the two systems differ, but this tpi system used to be a mass air flow unit, still has the 9th injector so putting a new harness in it shouldn't be hard I HOPE