After driving for 30 minutes or more or 25 miles,

Front Drive Axles Worn

Hello, have you tried to unhook the negative side of the battery for about 10 minutes and then go from there . It should reset the computer completely .

Sounds like you need to replace your ujoints. Or possably your carrier bearing. This is most common in these vechiles.And is part of your 100.000 mile tune up.If you need help replacing let me know.If you have to take to a shop it would cost around $50 plus parts. Best of luck to you and thank's for using Fix Ya

{: ) When the park assist system detects a hitched object behind your vehicle, it will normally display that "Park assist Blocked" message. You can still drive safely even with that message. When you're done, just remove the hook off. Turn off engine for a few minutes. turn it on again and drive your truck around for 30kmh or so, then test again the park assist system.

Hi, there is a park relay in middle of the interior relay box under the dash to the left of the steering column. This is shown on page 6-61 of your owner's manual (http://www.extendedgmwarranty.com/owners-manual/gmc/2001-GMC-Yukon-Denali.pdf)
With the battery connected, pull out the relay and push it back in. If it clicks when you do this, the headlight switch is bad. If it doesn't click, the relay is bad. Try swapping the relay with another similar relay, such as the horn or A/C relay. If that solves the problem you need a relay. If not, you need a switch. Please let me know if you have any questions, and thanks for using FixYa.

THE BELT TENSIONER MAY NOT BE WORKING LIKE IT SHOULD.
ALSO, THE BATTERY MAY BE GOING DEAD WHILE YOU ARE PARKED. WHEN YOU RESTART, THERE IS A VERY LARGE LOAD ON THE ALTERNATOR AS IT TRYS TO RECHARGE THE BATTERY. CHECK BATTERY AFTER IS SITS OVER NIGHT.]
ROBERT

The security system (Passlock) is having problems, it's typical on those trucks. You can find a great write-up here: http://newrockies.ca , it was the only thing that saved my Park Avenue.

Hey guy I had the same problem with my 2001 Yukon XL. I took it to the dealer and they charged me an arm and a leg for a diag which found nothing. I had the fuel filter changed which fixed the problem for a few months but the problem came back. I have a new car now and drive that most of the time. I came across a site and this guy said to clean the Throttle Body like this link says, http://www.youtube.com/watch?v=MnWiOrnVk28a and also clean the mass air flow sensor as this link says, http://www.youtube.com/watch?v=vPT8rL0noYg I also changed out the air filter. Fixed my problem, the engine no longer stalls and that idle flux has stopped also. I hope this helps you and anyone else who is having this problem.

Reggie

bad mass air sensor could be the culprit...it is by the air filter, be sure hose is secure and clamped

Easy fixes

1- get a can of mass air flow sensor cleaning solution and spray it on the sensor. The sensor is in line right after the air filter. It is in the tube that is directly connected to the box the air filter is in. You can see a wire connector going to it. Easy to open up, look inside and you will see some thin wires going across with a few nodes on them. Spray these clean. re-assemble.

2- get some fuel injector cleaner and remove the tube where it goes onto the manifold.Same tube air sensor is in, except at other end. Spray some cleaner in and run the engine. I am not a pro and I get scared there will be a fire so I reassemble the entire tube after spraying and before turning on the engine. I repeat it a few times.

#1 helps the most and you will be sooooo surprised how inexpensively you solved a seemingly major engine problem. I had the same thing when turning in a parking lot, slow turning. Problem gone in 10 minutes work!!!