Hey guys, been reading around on here for a long time but now I've got a problem and thought this was the place to ask. I just swapped in a vortec 383 into my 97 k1500, the issue I'm having is that it doesn't seem to be getting fuel to cylinders 2,3, and 5. I checked it by wiping a wet rag on the headers after it's run a bit. I pulled a plug and it's got spark. Does this sound like the poppets being uncooperative after the swap or could this be timing related? It doesn't start very well and really stumbles below about 1500rpm. The higher in the RPM range you get the better it sounds. I've also done the 0411 swap if that makes any difference, it's also throwing a P1336 code, no others.

thanks guys

ok, i know this may sound silly - but double check the timing with the crab cap - i know you saw spark, but is it at the right time?

if it is, i would say its a poppet problem, which is not unheard of, a tank or two of bad gas can screw them up pretty good and short of getting them out and having them tested, not much you can do to fix the issue easily...

i would suggest if you get into it that far, its best to just replace with the upgraded injector unit.

one more thing - who did the engine and was it ever running good and did you hear it run? if its not fuel or timing it could be bad cam or lifters not letting the valves open.....

Got the updated spider put in and it fixed the issue. thanks for the input.