Rough Engine 45mph+
 

Hey guys. I own an '06 H3 and I am experiencing a rough riding engine when I am traveling highway speeds. I just had all new Bilstein shocks installed and had the Chevy dealer do an intake and injector cleaning. When I am going 45mpg+ there is a noticeable vibration that, I assume, is coming from the engine. When I take my foot off the gas and "glide" the ride is extremely smooth. I do have a check engine light to replace the thermostat, which I am having done in 2 days.

Hopefully someone has had this problem and solved it.

Thank you.

You know what happens when you make an assumption? :D

When was the last time you had a tire rotation? The new Bilsteins are going to ride a lot different than mushy wore out old ones.



How much is the Chevy dealer ripping you off for the T Stat change? DIY is like $53 (T Stat and coolant) and a few hours time.

tire rotation?. i skipped it for 63000,no change in ride,handling, all tires look alike, getting close to new set time. maybe august b 4 winter!

Had a similar problem, it was a bad universal joint on the rear drive shaft.
OK at slow speed but over 40 MPH vibration started and got worse as speed increased.
Very easy fix, if it is get the greasable U Joint. they are @ $20.00

+1 on the universal joints. I have to believe if your engine has rough performance over 45mph you would have to see some kind of error code. What you are probably feeling is a vibration and starting with the drivetrain is a good choice. Check your universals, they do go bad causing all sorts of vibration problems with increased rpms..

Yes, that is the problem I am having. Everything is smooth and fine, but after a certain speed it is apparent. Any idea how to know which U joints on which drive shaft are the problem or should I replace all 4?

Rule of thumb. If the vibration is in your seat(butt) its in the rear, if it's in the steering wheel its up front.

Mine was the rear shaft and it was the u joint going into the rear-end.
easy to take off, remove the small nuts and clamps on the rear yolk pry it out of the yolk with a screw driver, drop the shaft down a little and slide it out of the transfer case.
the u joint that's not moving freely is the bad one.
I could not move my rear u joint. After pressing the old one out the needle bearings in the cap were just brown dust.
Moog makes a greasable one, well worth a few bucks more.
Go on you tube and search, there are videos to show how to change them.
If it is a bad u joint you will not believe how smooth and quiet it will be when fixed.

Thank you jonnieh3. I just ordered two Moog 232A's and two 225's. I feel the vibration in the seat and steering wheel (had throttle body cleaned), so I think replacing all four U joints would be the smartest thing to do.

I'll keep you guys posted if this solves the problem. Thanks!

You only have 3 u joints. Front has 1 rear has 2.

The front prop shaft has a funky joint that I can't remember the name of right now that attaches to the T case output.