2005 GMC Yukon runs terrible

[Anthony Jay Burt]

My GMC Yukon 05 model 5.3L was given to me by a friend because I had recently wrecked my 15 Silverado. I knew and he knew as well that the Yukon wasn't running very good. It would fire right up but it would idle as if out of time or something was stopped up. We put a scanner on it and we had so many codes pop up. the knock sensor code was the first one I tackled by replacing both knock sensors. replaced the intake gasket. I have put a new mass air flow sensor on it and plugs and plug wires.

after putting everything back together I cranked back up and it was running worst. clear the codes hooked it back up to the reader and had these 2 codes pop up. P0101(MASS AIR FLOW) even after replacing the old with the new . P0449(EVAPORATIVE SILONOID) I'VE GOT A BRAND NEW ONE BUT HAVEN'T REPLACED IT.

what should I do from here need help please point me in the right direction. What should I do next?

[Dnt]

Intake is cracked replace it.

[Anthony Jay Burt]

intake is a hard plastic but will an cracked intake cause it to misfire and not idle

[Jay P]

Yes... un-metered air will cause all kinds of problems. ECM sees less air than is going into the engine and sets fuel based on that. Your mass air flow code is likely related.

 

Jay

[Anthony Jay Burt]

I've been doing a lot of research also about the seriousness of the check engine light flashing continuously non stop. In more than one place I researched it has been repeated that the non stop flashing of the check engine light meant the problem was very serious . Will the cracked intake issue cause that check engine light to flash non stop. I ask this cause the intake isn't cheap and I would have to buy a new gasket yet again. Your insight is well needed and I thank you for your time trying to help