Hello all, we’ve had a 2007 CLK 350 for about 6 months now. We had the intake replaced the first month and a few weeks later I changed the magnets on the front of the heads (with help from this forum). But we still have one strange problem and it happened for the 3rd time this week end. After an extended drive on the highway, say 80 miles, using the cruise control at times, when we exit and are back on surface streets, the car does not want to shift properly. Saturday as I pulled away from a stop light it would not shift out of second gear. This has happened 3 times now and the fix as been the same each time. I pull over to the side of the road, remove and reinstall the air cleaner housing, and drive away. I don’t do anything else, just raise the air cleaner housing off the top of the motor, and put it back on. This first time this happened was a few days after the new intake was installed. I thought maybe a hose hadn’t been installed properly or something, so I removed the air cleaner housing to have a look and did find a hose disconnected near the side of the Mass Air Flow Sensor. I reattached the hose and everything worked fine. I thought I had fixed the problem. So when the car started shifting funny again a month or so later, I figured the same hose had come off. I pulled over to the side of the road and removed the air cleaner housing only to find the hose still properly connected. However after I reattached the air cleaner I was able to drive away and the shifting problem was gone.
Thanks for any help.
Any ideas?
augie

 

probably
they all fail eventually

go bosch if you do...

marginal pita to r/r
if you have done it, 10 minutes
if not figure 30

 

Thanks for the reply Wave, I’m assuming you think it’s the MAF sensor. If it was a $20 part I’d just change it and see what happens. My problem is not causing any codes either so there’s no help there. Maybe I’ll just change the air filters and clean the MAF for starters.
Thanks, augie

 

why spend $200 if you don't have too...

if nothing else you will know how to replace it if douching doesn't work. the plastic holder thing can be confusing so look closely before yanking it out.
i would suggest buying the two gaskets between it and the intake manifold before you begin

check for out of round on the top of the MAF and the gasket it sets into on the air cleaner which may be available as well

 

Actually, failing to shift from 2nd gear would not be caused by an engine malfunction. That is a symptom of "limp mode" which is an error condition within the transmission itself. You need to get the codes pulled (generic OBDII scanners won't work - you'll need someone with the dealer's SDS to do it). My guess is a bad speed sensor on the valve body.

 

Thanks for the reply Rudeney, is there a light that comes on when you're in Limp Mode? We didn't get any light on the dash. The car was in the shop last week for an O2 sensor replacment. The only other stored code they came up with was a SRS code for female end of the drivers seat belt. The belt works but they think there's a bad sensor in it. We're going back for that one, maybe next week.
All 3 times this has happened the shifting was affected a little different. The first time was the worst, the car would not shift out of first. Lucky that we were very close to home. The second time it would shift but very rough and late. This week end was about like the second time I guess. Each thime the car would go into reverse very hard, it would make the car jerk. Then, pop the air cleaner, put it back on, and Bob's your uncle (every thing back to normal).