I just got my 2000 GLE back from the dealership who replaced the ECU and updated it to work with the new MAF. I got it out on the highway and it has not improved in performance as far as I can see. It would not exceed 2500RPMs. It was also shaking slightly (maybe that's normal, idk). There are no more error codes. I was previously getting P0171 and P0174 but both were resolved after I replaced MAF.

What should I do now?

 

Take it back to the dealer and have them finish fixing it

 

I might do that.


Could this maybe just be some kind of ECU relearn process? I've heard that it won't run correctly after a new or reset ECU until after a certain amount of driving?