Hi Scotty,

Your videos are very informative and fun. I can tell you truly enjoy helping people with your expertise. Thank you!

I have a 2012 Chevy Traverse AWD with 213,000 miles. I bought it with 130,000 miles. 

No engine light or codes.

Symptoms:

Stumbles/bucks/hesitates at low speeds under light acceleration. If I drive 30 or 40 mph up a steep hill it stumbles constantly until I get to the top of the hill.

I also hear an intermittent low vibration sound in the front end passenger side at highway speed similar to the sound of traction control on an icy road in the winter. It seems like the front passenger wheel is bogging down or trying to slow down. 

GM parts replaced:

All 6 spark plugs and coils

Scope revealed clean valves 

All 4 VVT solenoids

PCV valve and made modification

MAF sensor

Air filter 

Cleaned throttle body and intake hose.

Upper intake treatment.

Front suspension is new.

Transmission was rebuilt at 153,000 miles including replacement of TCM.

My trusted local mechanic checked live data and told me everything was within tolerance levels including fuel trims.

Before replacing the coils on two different occasions I did have misfires in bank 1 and 2 as well as a random misfire with white smoke coming from the exhaust and limp mode. I was able to push through limp mode both times and get back on the freeway and make it home without incident. 

Since replacing the coils i have not had any misfires, but now I have the symptoms described above. 

I change oil regularly with full synthetic. 

I change transmission fluid every 25,000 miles. 

I realize these vehicles have chronic problems. 

Any parts you recommend I try replacing next?

Is there value in waiting for a code to trip?

Do you think a GM dealer would find the problem for a $150 diagnostic?

I really appreciate your help,

Randy Gnadke