Acts like it wants to run but doesn't.
- Thread starter NO4NSHIT
- Start date
-
- Tags
- 2003 yukon help newbie
Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.
Mudsport96
Full Access Member
Those super black ones almost look like the injectors may be hanging open and flooding the cylinders
So I've tried new coil pack on cylinder number one and still coming back with PO301 but it's weird because when it starts it will idle decently smooth you can still tell that there's a miss but not bad then in about 10-20seconds it will start idling rougher and start missing bad and then backfiring out exhaust but if you press the gas it'll sound like it kinda goes away a lil bit but still backfires.. I have new injectors on the way
rockola1971
Full Access Member
Did you try clearing all codes then starting? Doublecheck all sensors and make sure you plugged them all in to their wiring harness.
drakon543
Full Access Member
- Joined
- Feb 15, 2016
- Posts
- 2,473
- Reaction score
- 1,715
injector could definitely be a possibility with above stated symptoms. if that injector is trying to hard and clears up a bit when you open the throttle giving it enough air to burn the extra fuel out could be the case. what looked like oil can just be excessive carbon build up from a bad burn with a coating of wet gas. next time to try to run it and pull the plugs again hit that wet plug with a lighter. if it instantly catches on fire its definitely just wet with gas and flooding that cylinder.
injector harness could be a problem also, just food for thought and I would check the ecm harness, be sure it is clean and dry with no corrosion.
The AC delcos are 41-962
It's a 2003 Yukon XL 5.3 l Vin Z. I've already replaced all the fuel injectors new plugs and wires, mass air flow sensor, O2 sensors. It will idle smooth for probably about 30 to 45 seconds then start to slightly miss, then it would start to backfire like every 10 seconds it would hit a backfire. It threw up a po300 and a po301 and then a po171. I just performed a fuel pressure test on it it went up to about 46 PSI and then slowly began to drop I was just curious that would that be a bad fuel pump I don't know how long it's supposed to hold and you can't trust everything you read on Google..
