Major Drop In MPG
Thread Starter
Junior Member
Joined: Dec 2012
Posts: 24
Likes: 0
2006 C280 4matic
Major Drop In MPG
It's been a month or 2 since completing the 'A' service on my vehicle (oil change, new Bosch plugs, Mann air filters) and I've noticed a drop in my average MPG according to the computer. Before I averaged about 22 mpg and this has now dropped to 16. I've noticed that even during idle the mpg starts at around 18 but will quickly drop to 12 as I let the car warm up.
https://mbworld.org/forums/c-class-w...-low-idle.html
I should note that after doing the maintenance I was getting a CEL with P2190 and P2188 codes. This was because I didn't seat the air box properly and after getting it down tight the codes eventually went away.
There is no CEL present and the car seems to drive fine other than the drop in mpg's. I'm planning on replacing the fuel filter once it arrives since I'm not sure if it's been done yet.
Any suggestions or ideas as to why this sudden drop?
https://mbworld.org/forums/c-class-w...-low-idle.html
I should note that after doing the maintenance I was getting a CEL with P2190 and P2188 codes. This was because I didn't seat the air box properly and after getting it down tight the codes eventually went away.
There is no CEL present and the car seems to drive fine other than the drop in mpg's. I'm planning on replacing the fuel filter once it arrives since I'm not sure if it's been done yet.
Any suggestions or ideas as to why this sudden drop?
Thread Starter
Junior Member
Joined: Dec 2012
Posts: 24
Likes: 0
2006 C280 4matic
Thanks for the reply Phister.
I should've said that I cleaned the MAF before reseating the airbox since I was worried about dust and debris entering thru the gap created by the improper installation. Although I haven't checked the plugs again, I torqued them all to spec so I'm fairly certain they're in good.
I'm waiting on a new throttle body gasket so I was going to clean that and replace the fuel filter to see if it helps any. I'll recheck the plugs at the same time.
Any other ideas?
I should've said that I cleaned the MAF before reseating the airbox since I was worried about dust and debris entering thru the gap created by the improper installation. Although I haven't checked the plugs again, I torqued them all to spec so I'm fairly certain they're in good.
I'm waiting on a new throttle body gasket so I was going to clean that and replace the fuel filter to see if it helps any. I'll recheck the plugs at the same time.
Any other ideas?
