Replaced CATS mileage went down....
Thread Starter
Super Member
Joined: Apr 2003
Posts: 690
Likes: 33
From: Bay area - California
2000 ML320 2006 SLK 350
Replaced CATS mileage went down....
I had my CATS replaced 2 weeks back at the dealership....initially thought...the drastic drop in mileage from 16-18 (city) to 11-13 (city) would be short lived...but its been 2 weeks now and the mileage just doesn't wanna go above 13.8 (as per the trip computer)...is there something to watch out with the replaced CATS or will the mileage just move up gradually......
I know, a faulty O2 sensor could do this...but I would think they would have checked all of this while doing the CATS...
I know, a faulty O2 sensor could do this...but I would think they would have checked all of this while doing the CATS...
Thread Starter
Super Member
Joined: Apr 2003
Posts: 690
Likes: 33
From: Bay area - California
2000 ML320 2006 SLK 350
How else can the drop in mileage be explained...
Is there anything other than the O2 sensor that could cause the drop in mileage??? I know it has to do with the replacing the CATS event....while taking my car out of the dealership after the fix, the mileage read 11 mpg...and has been between 11 and 13.8 ever since...
I had left it in the dealership for the CAT work while it was showing 16.2 mpg on the trip computer...
My mileage has never moved above 13.8 mpg ever since I brought it back after the CAT replacement...
I had left it in the dealership for the CAT work while it was showing 16.2 mpg on the trip computer...
My mileage has never moved above 13.8 mpg ever since I brought it back after the CAT replacement...
MBWorld Fanatic!
Joined: Nov 2001
Posts: 4,260
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From: Philadelphia area
2010 ML550, 2010 E350 4M, 1966 Corvette Convt C2
Reset the trip cpmputer avg mile mode, drive it for a week or so and see what it says. Could be due to the dealer idling it in the shop for a couple of hours
Thread Starter
Super Member
Joined: Apr 2003
Posts: 690
Likes: 33
From: Bay area - California
2000 ML320 2006 SLK 350
Still no luck...
The MB shop can't explain the drop in mileage...best they could come up with is a suggestion to change gas station from Chevron to Shell for a few tanks and see if that helps...
ML God, you were right...I was told by my technician that it was impossible to get an O2 sensor installed wrong..since there are 4 of them..and each one is of a different shape..hard to get a wrong one in at the wrong place...
But the mileage problem still continues..
Got my motor mounts replaced by the way...and it made a big difference in the drive feel..much smoother and vibration free than before...
What I couldn't understand is why is changing of motor mounts so labor intensive..
I was charged $46 for the motor mounts and $250 for the labor...I would think changing motor mounts wouldn't be more than an hour worth of work...
ML God, you were right...I was told by my technician that it was impossible to get an O2 sensor installed wrong..since there are 4 of them..and each one is of a different shape..hard to get a wrong one in at the wrong place...
But the mileage problem still continues..
Got my motor mounts replaced by the way...and it made a big difference in the drive feel..much smoother and vibration free than before...
What I couldn't understand is why is changing of motor mounts so labor intensive..
I was charged $46 for the motor mounts and $250 for the labor...I would think changing motor mounts wouldn't be more than an hour worth of work...
