2008 GMC Yukon Denili

[Burkard]

Hello everyone. I have a problem with my 08 GMC yukon Denali. When I go pick up my son from school there is always a long line so I end up sitting idle for a good 10 to 15 minutes. I turn off my AC and roll windows down during this time. As soon as a good to leave it starts acting funny it started off like it was idling bad. My check engine light was on went and got codes read found out it was the purge valve replaced it reset check engine light and it went off and never came back on so I thought I fixed problem it ran good for a month then started doing it again. But this time it would only do it as I let off of gas and was going to brake. As it was doing this I shifted it into nuetral to see if it was transmittion but it continued to shake. Its not the engine I would think because the rpms stay at less then 1000 and not jumping up and down. I was thinking brakes maybe warped rotor. If anyone else has had this problem could u help out a brother. Thank u Jason

 

[wsteele]

Hello everyone. I have a problem with my 08 GMC yukon Denali. When I go pick up my son from school there is always a long line so I end up sitting idle for a good 10 to 15 minutes. I turn off my AC and roll windows down during this time. As soon as a good to leave it starts acting funny it started off like it was idling bad. My check engine light was on went and got codes read found out it was the purge valve replaced it reset check engine light and it went off and never came back on so I thought I fixed problem it ran good for a month then started doing it again. But this time it would only do it as I let off of gas and was going to brake. As it was doing this I shifted it into nuetral to see if it was transmittion but it continued to shake. Its not the engine I would think because the rpms stay at less then 1000 and not jumping up and down. I was thinking brakes maybe warped rotor. If anyone else has had this problem could u help out a brother. Thank u Jason

Your description is a little confusing. When you say it came back, did the CEL come back on, did it produce a DTC?

On the vibration, is it before you apply the brake ? (i.e. coasting).

 

[Burkard]

Yes it happens while I'm coasting. No engine light. Sorry about the confusion. It runs good driving around town. It only does it if it sits idling for a long period. Sitting in a long line at bank, school, etc.

 

[wsteele]

Yes it happens while I'm coasting. No engine light. Sorry about the confusion. It runs good driving around town. It only does it if it sits idling for a long period. Sitting in a long line at bank, school, etc.

It could be that you have a brake puck that is sticking in the caliper. When you are sitting idling, try shifting into park and foot off the brakes, see if it comes back anyway.

 

[Burkard]

Ok I'll try that thanks for advice

 

[wsteele]

Ok I'll try that thanks for advice

Another thing to check is when you notice the vibration for an extended period of time, if you have one of those infrared cooking thermometers, when you stop shoot the laser dot at each rotor and caliper through the slot in the wheel. If one is dragging it will probably be a LOT hotter than the other side. You can probably detect it just from the temp of each wheel if it is dragging badly.

If you find the above is the case, get that caliper addressed soon.

 

[Burkard]

Thank u. I believe its something to do with the evap system. It started to do it again so I pulled over and loosing the gas cap and it stopped doing it. Weird that its not throwing a code. Im gonna check all the hoses and charcoal canister. Ive replaced everything else on that system.

 

[wsteele]

Thank u. I believe its something to do with the evap system. It started to do it again so I pulled over and loosing the gas cap and it stopped doing it. Weird that its not throwing a code. Im gonna check all the hoses and charcoal canister. Ive replaced everything else on that system.

If you get it figured out, definitely post your results so others who might be seeing the same thing can benefit. Good luck.

 

[Burkard]

I finially found the culprit, it turned out to be the front passenger caliper sticking. After I went through the evap system. I cleaned out all hoses and the charcoal canister. I decided to jack it up and took off the front tires. Tjen started checking out the brakes after noticing the passenger brake pads where almost worn out and driver side was still farely new. So I went ahead and bought two new calipers. And brake pads and put them on. So far so good. So hope this helps out anyone that might have similar problems. Thanks everyone for all the great advice.

 

[Burkard]

Hey guys,
Sometimes I could bang my head up against this Denali, after I replaced both front calipers on me and the family took a ride to the beach. After getting to beach I turned the truck off got out and got a familiar smell coming from the passenger front tire. Knowing by the smell it was burned brake pads. Pissed I got everyone back in Denali and went to parts store and got the rubber brake line going to caliper. Went home and put it on. After driving around all day today no problems. Next time I'm gonna start with the cheapest part first. At least know I know I have brand new calipers on the front even though I proable didn't need to replace the old ones. Hopefully someone else learns something from my mistake. The rubber hose can look good but it can collapse on the inside there is enough pressure to apply the brakes but then it collapse because there isn't enough pressure to release the caliper. Everyone drive safe and god bless all.