mncowboy2001

Once I put the upper plenum back on clean the plugs and try to start it and check for any vacuum leaks and check the exhaust manifold gaskets thank you for the advice

I have a 99 gmc suburban 5.7 running rich fouling plugs to the point it wont start. New fuel pump filter and poppet injector set. True duel exhaust with no muffler but still has cats under it. No code coming up and not sure what else to do. once running I can get it to go down the road it runs great. off the line falls on its face and can smell gas from the tailpipe and black sooty smoke at idol runs like crap. Popping out the exhaust. what else can it be. This thing has me boggled.