GMC Sierra starts but will not run.
Hi everyone. I'm having problems with my 5.3L. I bought it in 2006 with 100k miles on it and sometimes on a cold day it will run perfectly fine for 5 sec or less and then cut off. It's been doing it for 8 years now and it's gotten worse and worse. Yesterday in 1 degree weather it left me stranded. Today in 10 degree weather it will run slightly longer but no luck keeping it running. Like I said it will run for just a few seconds then sometimes cut off with a pop or backfire. No check engine light. After it cuts off I have to wait a few minutes to try again. If I don't the engine will crank but won't fire. Also sometimes the gauges will go crazy(speedo pegs out, no fuel, check 4wd) and the door chime will stop working. If you touch the throttle at all it will immediately cut off. I can smell gas and there is blue smoke coming out the exhaust. MAF sensor has been replaced as well as fuel pump and fuel filter. Fuel pressure is reading 55 pounds the whole time. Sometimes disconnecting the battery and reconnecting seem to help but I'm not too sure. It does have a pretty big stereo and the starter and battery are brand new. So far I've been told it's the intake gasket or the throttle position sensor but I think it may be something else. Bad battery cable perhaps? Any help would be appreciated. Believe it or not it's sitting in a parking lot across from a GM dealership so even if we can figure out how to get it moving for 300 feet that would be great! Engine runs fine once it gets going and displays no codes on a SnapOn reader. No check engine light. Only messes up below 40 degrees and the colder it gets the worse it is. Usually after 5 or 6 attempts it gets going but not this time. Engine is all original 334,000 miles :-)