2 weeks ago I took my 07' Caravan SE 4cyl to the dealer to fix a p301 code. They dealer had the head machined and the valves replaced. But in the weeks since ther van is ruff idling, hesitates or stutters when the gas petal is depressed, and gas mileage has gone down noticeably. And this morning the check engine light came on and a P0068 code is displayed on my scanner. Is this a faulty TPS or MAP? And is it possible that the dealer missed a step in my first repair?

 

Dealer miss a step? That's a given. Anything is possible. The work they performed had a warranty. If you're within it, they will fix it. The TPS and MAP sensors and all they attach to have to be removed to get at the heads.

 

well what i have read if your has a plastic intake manifold could have a crack in it. maybe not put back on and its seal not right. also the fresh air make-up hose could have crack and leaking. pcv stuck also. check all hoses vaccumm leak. then see if it could be a faulty manifold pressure sensor or a faulty throttle position sensor. then i would check any wiring that either not connected or broken.