08 Yukon Denali mysterious problem?


#1

Hello! I have an 08’ Yukon Denal XL and I have been experiencing an issue ONLY while the car is in drive and ONLY from a cold start and while outside temperatures are very cold as well, like freezing temps. When I start my car and drive it immediately, the first couple times I come to a complete stop and it has a vibration that reminds me of the feeling you get in a car that is a stickshift and you don’t push the clutch in, the car does not stop as it normally does, it will come to a stop but rolls a little past where it should and as the car stops, the idle gets super rough and usually the car will completely stall out. It re-starts right after. The car will do this 3-4 times and then won’t do it again until the next time I drive it from a cold start again and in cold temps outside. We were told this was a bad solenoid that was inside the transmission. We got 2 other opinions and were told this was a bad throttle body-also had a code suggesting this I believe. After having the part replaced, the car seemed fixed for approximately 4-5 weeks. Now the car is doing the exact thing again. I have also noticed lately, that sometimes when I go to accelerate after already driving on the road, coasting and then press on the gas petal again…the car doesn’t immediately accelerate, it bogs down, almost like a choking sensation and then it will accelerate. I’m not sure if this has anything to do with my big problem, but it never used to do this. I just started noticing this right after having a new throttle body put on. ??? Please help!!!


#2

Please tell us the codes that are present.


#3

No codes present now. The only code was for the throttle positioning sensor. It went away after the repair.


#4

Try doing a throttle body relearn procedure to see if that helps.

https://www.bing.com/videos/search?q=08+yukon+denali+throttle+body+relearn&pc=cosp&ptag=G6C999A005A2B4283&conlogo=CT3210127&ru=%2Fsearch%3Fq%3D08%20yukon%20denali%20throttle%20body%20relearn%26pc%3Dcosp%26ptag%3DG6C999A005A2B4283%26form%3DCONBDF%26conlogo%3DCT3210127&view=detail&mmscn=vwrc&mid=214FD10F9DD67974F023214FD10F9DD67974F023&FORM=WRVORC

Tester


#5

The engine management may not be correctly adjusting the idle speed for engine load. Try a few experiments

  • When the engine seems bogged down, stopped, foot on the brake, and in D, does it unbog when putting the transmission in N?

  • Same thing, but instead of N, try putting it in other gears (R, 1, 2, 3 etc).

  • With the engine bogged down in D as before, what happens when you turn on the headlights to bright?

  • As above, what happens when you turn on the AC to max cold?

  • As above, what happens when you turn on the rear window electrical defroster?

  • As above, what happens when you turn the steering wheel slowly left and right?


#7

I will have to try these and update!


#8

Kept up on trans fluid changes? in 2wd or auto?


#9

I don’t believe we have ever changed the fluids since we have owned the car. Its AWD.