i have a 2007 hummer h3 lux and have the 16" 265 series tires on it and the tpms light turns on and off randomly, the dealer says i have the wrong tires on it and need the 285/75r 16 tires and they cant do anything about the tpms light.... does that make sense?
Also, the engine sounds like a diesel engine at times... not all the time and it will vibrate the whole car.... ive noticed it does it when the tpms light turns on???
driving it feels like the tires arent round but oval like- had tires balanced and im still having the same problem, the steering wheel shakes back and fourth, and does so violently on the interstate making it very scary to drive it on the interstate.
when i hit the smallest bump in the road the rear door sounds like its about to fall off, have taken it to 2 different hummer dealers and everyone says there is nothing wrong with it... this is my 2nd h3 and i never had these problems in my first one.
any ideas??

 

Your I5 is never supposed to sound like a diesel. Have the dealers just not been able to reproduce the issue? Clearly that is not correct. If your truck didn't have the adventure package then the 265 tires would be correct. If it did then the 285 tires are correct.

 

changing the tire size will not affect the tpms... there is something else wrong there. This has been discussed before and you most likely have a bad sensor or a bad battery in one of the sensors.

As for vibrations.... no answer for you there.

 

They did offer the 285s on the luxury models with the upgraded suspension. I guess it was a rare option to find the luxury model with the locking dif and upgraded suspension but they did offer it in the luxury model. Easiest way I found is to go to tirerack.com and it asks which luxury model you have, if it's just the regular lux it shows the 265 tires, put the off road luxury and it puts the 285- not only that but I have the window sticker which shows the added $ for both those items. As far as sounding like a diesel, it only seems to sound like that when the tpms light comes on which makes absolutely no sense whatsoever(tpms light turns on and off as it pleases, but mainly turns on at highway speeds, then just comes and goes)