93 5.7 intermitten miss

i have a 93 k1500 5.7 4spd automatic 4x4 most of the time this truck runs like crap (sputtering low power rough idle etc.) but maybe once or twice a day it will run like a champ.i have replaced just about everything there is on the motor and the motor itself the only things left from the previous owner are the throttle body,egr valve,water pump & altenator.yesterday i installed a brand new gmac distributer & it helped a little but not quite enough my mechanic buddy suggested that i aquire a tpi unit from a corvette with computer & all and install it in my truck does any1 have any feed back on this tpi thing or any info on what the heck is keeping this truck from performing as it should i have roughly $35,000 wrapped up in this truck so i cant really get rid of it without losing my ass.HELP ME!

I am no TPI expert, but I would look at the basics first. Check for vacuum leaks, could be at intake or a bad hose that's just cracked and you can't really tell it's bad. Check them all real good.

I'll tell you I had a TON of problems like this and it turned out to be bad plug wires. I put new wires on and still had the problems until I took some of the wires out of the factory seperators and re-arranged them so that there was lots of air space between each wire.

I would carefully look at all the basics, before starting to spend money on the big stuff.

Alot of what you describe can be caused by a sticking egr valve. But I am no mechanic just a home fix it guy. I am confused though. Did you mean TBI or TPI?

Alot of what you describe can be caused by a sticking egr valve. But I am no mechanic just a home fix it guy. I am confused though. Did you mean TBI or TPI?my truck came stock with a tbi fuel delivery system on it which i am considering converting over to (computer & all) a tpi system,and am wondering if any1 else has done this & how it is working out for them.

Im pretty sure the heads are different.Make sure the manifolds have the same bolt patterns.Reason I say this I did a head chng & the parts store sent me tpi heads that did not match my tbi intake.Got the right heads & bolted it up.I also agree with chevyss that it sounds like bad wires.

When you replaced the distributor did you check the bushings? The shaft may be wobbling and screwing up the timing. Also, have you checked the timing?