I have a 2015 GLK350 with about 21k miles on it. After I took it on a long 500-mile trip, and had to give it a 5-second WOT on the freeway at one point, from a standstill, for very quick (and noisy! - engine really revved up) emergency acceleration, now I experience throttle lag/engine hesitation when starting to move from a standstill or when trying to quickly accelerate from a slower speed. Also, the fuel efficiency has decreased some: on the trips where I was previously able to get 29-30-31 mpg (YES!), now it only goes up to 25 mpg; and on those where 26-27 mpg was the norm, now I can only get to about 21-22 mpg.
Having already read some of the forums on here, I've tried to follow the procedure to reset my TCM a couple of times. Each time, the reset does help "wake up" the throttle quite a bit, yet only at first; during the very first trip, it seems to slowly "dumb down" again.
Also, during idle, the engine seems to sound a bit rougher than usual; and during the initial acceleration from standstill, it now sounds a bit like diesel (this is a gasoline engine taking 91 gas.)
The vehicle is fairly new and is still under warranty, so I really can't imagine something going wrong in the engine or the transmission simply from that 5-second emergency acceleration on the freeway. Could this simply be a TCM or ECM software issue? Thank you for sharing your opinions and advice on the above.
Having already read some of the forums on here, I've tried to follow the procedure to reset my TCM a couple of times. Each time, the reset does help "wake up" the throttle quite a bit, yet only at first; during the very first trip, it seems to slowly "dumb down" again.
Also, during idle, the engine seems to sound a bit rougher than usual; and during the initial acceleration from standstill, it now sounds a bit like diesel (this is a gasoline engine taking 91 gas.)
The vehicle is fairly new and is still under warranty, so I really can't imagine something going wrong in the engine or the transmission simply from that 5-second emergency acceleration on the freeway. Could this simply be a TCM or ECM software issue? Thank you for sharing your opinions and advice on the above.