Ok well i just bought the wife a 2500 yukon xl today and it has the 8.1L in it, love the truck and have been looking at getting a new denali with the 6.2 but this deal fell in my lap and is a better plan for the end result then the 1500 chassis as i plan on a dmax/ally swap(now i dont have to by 2 vehicles).

Anyway its an 05 and i just picked it up today from the dealer went to the gas station and topped her off with 91. Well i restarted and pulled out waited at a light with no issues, once i turned the corner and gave it a little it started bucking raising and dropping rpm's then i let off as it kept doing it then it just died.

Thank god the next light was red, as i coasted up to it in neutral i just turned the key off restarted and pulled into the next station to see what would happen. Well as i figured it hasnt done it since and this is gonna be the long haul trip vehicle so im curious if this is a common thing or not cause if it is im taking it back, if not whats the deal cause ive racked my brain trying to think of what it is but came up with jack.

 

WOW 54 views and nothing haha.

Anyway i think i have linked this to every time i fill the truck with fuel. It will run fine then i fill up, once done it will idle fine and ill drive off. oncw on the road for maybe 1-5 minuites it will start cutting out and bucking till it either dies or works through it.

What is causing it, i am still trying to link it to when i feel up which is hard to do not driving it everyday and the fact it has a 37 gal tank or something haha takes a while but i spose i could just top off and see if it does it.

ANY input is appreciated, in december im taking almost a 2k round trip home and back for leave and need this issue fixed.

 

No codes?

 

No sir there werent any codes to be shown except for the MAF code which was caused by me, this issue happened before that anyway.

Although i put her to half a tank twice now with no issues so i dont know why it would do it when topping the tank and not when putting fuel in other than the crank sensor. Every now and then i can feel it studder while driving and with that incident taking off from the light im leanin hard to the sensor

 

my truck used to surge really bad at stop lights and low throttle i found that i had a bad gap on a plug it would run alright under load. just an idea to check

 

Yeah it stopped doing it all together now wether i fill to the top or not, i have regapped new plugs to the suggested gap though it stopped before i did that.

Dont have a clue why it did it but it was wierd it was only when i topped the tank, im cool now though as said it has stopped all together.

Thanks for the reply though.

 

Hmmm, glad it seems to be fine now. I wonder if you got some water in the tank from the first time you filled it up after buying it.....?

 

Hell i dont know it never threw any codes and it quite out of the blue so its got me stumped but im cool if its cool haha.

 

The truck's EVAP purge valve isn't sealing when off. Since it pulls fuel vapors off the top of the tank, when the tank is full and the valve is open at all it can pull fuel into the intake manifold and flood the engine. The ECM doesn't even run the purge valve when the tank is above 85% full for this very reason. It could be intermittent but since it's easy to get to under the hood and affordable I'd replace it.

Vernon

 

Thanks for the input bud if it starts acting up again ill change it.