Ok, been having lots of issues with my truck lately. Most notable is the one that I can't figure out what the hell is wrong. I was convinced that it was something with the motor and that I had a miss or fuel injector problem or something. But, now after checking or correcting the issues that I thought were a cause from the motor, I am still experiencing my trouble.

It has been doing it for a while, but seems like it has gotten worse over the last few weeks. It doesn't do it all the time but does more than not. But it is jerky or feels like the truck is jerking or surging like someone is lightly tapping the brakes. This mostly is noticable when slowing down to a stop, it does do it too though when the truck is basically in cruise control or if I am physically maintaining speed. I am wonding if maybe I am having transmission problems or rearend problems. Wheel bearing, driveshaft slop, torque converter maybe? I have no idea what the hell it is but it is driving me absolutely crazy. It has not thrown any codes what-so-ever and it is not driving bad except for this. The motor is strong and runs like hell. I have noticed though that it does feel a little less ballsy from a stop.

 

I have noticed something like that when at extremely low speeds and applying the brakes. Like when I am decending the parking garage at work. I just figured it was time to get the brakes and rotors checked out.

 

i have been having some of these issues with mine since day one. i have had, since the day the truck rolled off of the lot, the "bucking", for a lack of a better term, when coming to a stop, but also when at a stop and slightly letting off of the brakes the truck will jump/surge forward some. i have had it back to the dealer numerous times for the surging at a stop and there answer was the rotors were bad. yeah, ok. the rotors are good.

i started looking into this some and am thinking it may be related to timing, specifically when the Main spark table is used vs the Base spark table, and the Overspeed/Underspeed values. using HPT to scan, i have noticed when at a stop the surging seems to coincide with timing jumps. if i keep my foot on the brake and don't let the truck move it won't surge and the timing pretty much stays flat-lined, +/- no more than a couple of degrees, but if i let off of the brake some i will notice the timing will start to jump around a bit and that's when the surging will start. it is mainly with the a/c off that the surging is more noticable.
i am also having issues with a low rpm, moderate speed cruise with a slight acceleration, where i am getting a shimmy in the truck that is coming from the rear. it kind of feels like what a out-of-balance driveshaft would but instead goes away with increased speed/rpm, or a rear wheel that need balancing. it comes and goes never consistent. dealer said it was my exhaust. it may be related to that since my exhaust does exit before the rear wheel on the same side. i have noticed that it is significantly worse with a side wind. i was thinking it may be torque converter related so i took it in to the dealer (warranty) and they replaced it along with new leaf springs because of a sqeak, and the leaky rear trans seal. didn't fix the problem. not better, but not worse either.

 

Well ****, at least I know now that I'm not the only one having these problems. I was beginning to think I was. Its just been driving me crazy to a point where I am considering getting rid of the truck.

 

How long have you had the throtle body?

 

I have a 2005 Yukon Denali XL 6.0 that from day one has a jerking motion when slowing down into first gear. This is helped a littl by having the foot firmly on the brakes at the time. I was and still am going to change the transmission oil as a matter of fact just to see if it eases the situation. It appears to me as if pressure is being retained within the transmission and only released when in the motion of the changing down in gears.
Any additional information would be appreciated.
Regards,
Graeme D

 

wow this thread is almost a year old, but I think you probably got some warped rotors causing your issues.