Clunk heard when letting on/off gas?

[TGCOFTN]

Originally Posted by dbartromsut

Yep, my 08 does the same thing! It doesn't really sound like it is coming from the engine, so I don't see how running low octane fuel would make it do that. To me it sounds like its coming from the rear end... But mine does it and I do run 87 octane, so maybe. I'll try premium for a while and see what happens! You guys get way better mileage than me! I am lucky to get 10.5 mpg on the highway, but I would imagine that my tires, wheels and lead foot have to do with that!

Wow........10.5 mpg.....I dont recall getting that low in my 08 or my 07 H2.
You should try switching to premium and see if you see a increase in miles per gallon. I have been on a trip in my 2008 and ran it 75--80mph and got 13.8mpg. The only thing I can think of is maybe its your tires where mine are factory and yours are oversized.........and then of course running on regular unleaded. For me, I can go more miles on a tank of premium than I can on a tank of regular. With the regular you may save a buck or two at the pump, but on mine, when hitting a hill, it downshifts and acts as if its starving for power. So the buck or two your saving at the pump, your just blowing it out your tailpipe.

Try running a few tanks of premium in it, and see if it improves.