I have a 2012 acadia 130,000 miles. I am only owner purchased new 0 miles ayahuasca 2012. It has been a really good car for us. Yes there have been a lot of recalls and a few minor things happen. But this has been the only main problem. Last summer 2016 it started with a slight intermittently jerk or shudder at all different speeds. It didn't do it all the time or every time we drove. Slowly it has gotten worse to we're now it is almost a constant jerking or shudder. I am not sure really how to explain other than it feels like it looses gas while it's doing the jerking and will continue to go. It only does it under slow acceleration and while going at highway speeds. If I let off gas pedal or punch the gas pedal it stops. If I take off fast throttle it never does it. It starts and idles great. There has never been engine codes.
We have changed out spark plugs back with the same ac delco factory brand. We changed all 6 ignition coils. Replaced the purge valve solenoid sensor due to it making a clicking sound. Transmission fluid looks good no burnt smell of any kind. It shift great and no slipping. So I don't think it has anything to do with transmission. We have checked for vacuum leaks, don't appear to be any unless we missed them. Cleaned the MAF sensor, cleaned MAP sensor, cleaned throttle body, changed air filter and put some strong cleaner thru gas tank several times. Nothing has seemed to help. I don't want to keep spending and not fixing it. Anyone have any ideas on what else it could be?