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Gunvir Singh
Gunvir Singh,
Category: Car
Satisfied Customers: 1644
Experience:  Master Tech at Kennesaw Auto Tech
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I have a 2008 GMC Yukon Denali. it has recently seem to lose

Customer Question

i have a 2008 GMC Yukon Denali. it has recently seem to lose power while i am driving. as in, if i push the gas pedal nothing happens - engine won't rev, car will barely move, maybe like 2-3mph. every time i have turned it off, waited an hour or so, and then i'm able to resume driving. I am wondering what could be causing this problem.
Submitted: 1 month ago.
Category: Car
Expert:  Gunvir Singh replied 1 month ago.

Hello, let me review your request. Please stand by.

Expert:  Gunvir Singh replied 1 month ago.

Does any malfunction indicator come on the instrument cluster when the issue occurs?

Customer: replied 1 month ago.
nothing comes up on the cluster.
Expert:  Gunvir Singh replied 1 month ago.

DOes ot happen more when engine is cold, warmed up or just anytime?

Customer: replied 1 month ago.
it's happened twice. one time i had been driving the car around for a while, back and forth in the city for about an hour or so. the second it was 3 minutes into my morning drivie
Expert:  Gunvir Singh replied 1 month ago.

The symptom you are experiencing with gas pedal and no malfunction indicators on these vehicles usually points towards a failing throttle motor which is part of the electronuic throttle body.

Customer: replied 1 month ago.
I'm sorry. My Yukon is an 07. I just realized that I typed 08 by mistake. I'm assuming it's the same thing, but just making you aware.
So is the fix replacing the entire throttle body?
Expert:  Gunvir Singh replied 1 month ago.

Its the same on both years. Complete throttle body assembly will need to be replaced and idle relearn procedure will need to be performed afterwards.

Expert:  Gunvir Singh replied 1 month ago.

Do you have any other questions?

Customer: replied 1 month ago.
Sure, one more. Say I swap out the throttle body assembly, and it continues to happen. Is there anything else that could be causing the issue?
Expert:  Gunvir Singh replied 1 month ago.

Failing crank sensor can also cause a similar symptom but usually it will give the check engine light. Alsop make sure all the fluid are topped off and it is is not running hot when it dies.

Customer: replied 1 month ago.
would that just be a bwd sensor?
Expert:  Gunvir Singh replied 1 month ago.

Yes.

Expert:  Gunvir Singh replied 1 month ago.

Please read this:

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Expert:  Gunvir Singh replied 1 month ago.

Hello, just checking if you have any other questions?

Customer: replied 1 month ago.
I'm trying to remove the starter, but the lip that goes into the transmission won't come out. I've remove the two bolts- what's holding it up?
Expert:  Gunvir Singh replied 1 month ago.

It is held by two bolts, probably jammed inside as it has not been removed in a long time. I have attached the manufacture provided procedure to replace the starter.

Customer: replied 1 month ago.
got it all done. however, when i was driving around today i came to a stop light. when i went to drive off it happened again, except this time the rpms revved. i turned the car on and off, and after i put it in drive it seemed to go into the forward motion a little rough, almost like it hit a little, and then i was able to drive off. why would this be happening?
Expert:  Gunvir Singh replied 1 month ago.

Did you replace the throttle body?

Customer: replied 1 month ago.
no. just the sensor. would a faulty throttle body allow the engine to rev at 3-4rpms while not moving at all? almost like if i was in neutral?
Expert:  Gunvir Singh replied 1 month ago.

Which sensor did you replace?

Customer: replied 1 month ago.
the crank sensor you said could be the other possibility for the issue.
Customer: replied 1 month ago.
turned out the engine light was on, so i figured i would start with the sensor since it was the least expensive fix, and then move on to the throttle body if that didn't work - but having the engine rev while the issue occurred made me wonder if the diagnosis was correct.
Expert:  Gunvir Singh replied 1 month ago.

Did you get the codes read for the check engine light?

Customer: replied 1 month ago.
i did not. but it is no longer on.
Customer: replied 1 month ago.
i guess i can drive over to the autozone and get them to read it. here is my fear - is there any way this could be the transmission failing? is there a way to tell if the transmission is having issues? if it is, is there any fix besides replacing it? and if there is not, what is a replacement cost at a shop usually run?
Expert:  Gunvir Singh replied 1 month ago.

The Throttle body can give you the issue you are experiencing. The TCM gets reference from the thorttle body. If codes are present in the system, i will recomment to get it scanned to be certain of the issue.

Customer: replied 1 month ago.
ok
Expert:  Gunvir Singh replied 1 month ago.

Keep me posted.

Customer: replied 1 month ago.
the car didn't spit out any codes. only thing that the dash is saying is to service the park assist. other than that, no other notifications. no issues as i drove it to auto zone this morning, but it was just a*****
Expert:  Gunvir Singh replied 1 month ago.

Did you disconnect the battery when replacing the crank sensor?

Customer: replied 1 month ago.
oh yeah. completely. I replaced the battery - so brand new battery in there
Customer: replied 1 month ago.
My wife drove the car all day yesterday without an issue until about 7-8pm, when the issue i reported happened.
Expert:  Gunvir Singh replied 1 month ago.

There is a possibility the check engine lights codes cleared when you disconnected the battery. In my experience he symptoms you are experiencing do pont towards the throttlr bode failing but will need to wait for codes to come back to confirm.

Customer: replied 1 month ago.
you think that the throttle body issues could be mistaken by someone without experience as a transmission issue?
Expert:  Gunvir Singh replied 1 month ago.

Yes.

Customer: replied 30 days ago.
Read the codes. these were the 4 it spit out:
C0900
P2723
P0573
P0700
Expert:  Gunvir Singh replied 30 days ago.

I'm offline for the day. I will opt out and let another expert assist you.