Bad Gas Mileage/RPM's surging at cold start

bmac002 · 12-19-2002, 03:58 PM

I recently had my MAF sensor go bad and the dealer replaced it. Ever since then I have been getting terrible gas mileage but the car does not seem to drive any different. Also, occasionally (twice now) when I start the car the RPM's surge all the way to 2500. I know that is bad because the engine at cold startup does not have oil throughout the complete engine. Any suggestions are appreciated. I have notified the dealer but they are 2 hours away and I refuse to take my car to the dealer here in Wilmington (completley incompetent). I will take the car in after the first of the year unless people here think that it needs immediate attention.

Thanks,
Brent

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mdp c230k · 12-20-2002, 10:18 AM

They might have knocked the wires to the cold start valve lose as it is near the MAF. It richens the mixture to aid in cold starts and if it never turns all the way off you will have bad milage but no real noticable difference in drive. Get it checked soon but don't freak out over it.

bmac002 · 12-20-2002, 03:29 PM

Thanks,
I will have them check it when I am back in Raleigh.

Brent

bmac002 · 02-19-2003, 06:04 PM

The dealer in Raleigh has now stated that everything is running within spec. They claim it is not running rich or anything like that. They reset the driver adaptation and my service report says that they suspect it is transmission related?? Can anyone comment on this? I really don't believe it and have only gone through 1 tank of driving the car very hard becuase of the reset adaptation. Because of the hard driving I cannot tell if the mileage has improved. Now that the transmission adatation was reset the car does seem quite a bit more responsive. Any comment would greatly be apprecited. This transmission thing seems odd to me. The tank of gas that I have been driving hard on is time to fill up and it looks like I am only going to get about 17mpg. That is low isn't it? Even for driving very hard throughout the entire tank?

mdp c230k · 02-19-2003, 06:18 PM

I drive very hard and get about 14 mpg over a whole tank! Be happy with 17 mpg.

12-20-2002, 10:18 AM	#2
mdp c230k Super Member Join Date: Jan 2002 Location: Los Angeles Posts: 875 Drives: 2002 c230k	They might have knocked the wires to the cold start valve lose as it is near the MAF. It richens the mixture to aid in cold starts and if it never turns all the way off you will have bad milage but no real noticable difference in drive. Get it checked soon but don't freak out over it. __________________ '02 6spd C230K in Bril Silver w/C2, Eibach springs and sways. R1 Concepts Drilled/Slotted rotors F&R.

12-20-2002, 03:29 PM	#3
bmac002 Member Join Date: Nov 2001 Location: Wilmington, NC Posts: 135 Drives: CLK 320	Thanks, I will have them check it when I am back in Raleigh. Brent __________________ 1999 CLK320 Blk/Blk H&R Springs Bilstein Shocks K&N Drop-in BBS RX 18x8 s-03's V-1 Hardwired

02-19-2003, 06:04 PM	#4
bmac002 Member Join Date: Nov 2001 Location: Wilmington, NC Posts: 135 Drives: CLK 320	The dealer in Raleigh has now stated that everything is running within spec. They claim it is not running rich or anything like that. They reset the driver adaptation and my service report says that they suspect it is transmission related?? Can anyone comment on this? I really don't believe it and have only gone through 1 tank of driving the car very hard becuase of the reset adaptation. Because of the hard driving I cannot tell if the mileage has improved. Now that the transmission adatation was reset the car does seem quite a bit more responsive. Any comment would greatly be apprecited. This transmission thing seems odd to me. The tank of gas that I have been driving hard on is time to fill up and it looks like I am only going to get about 17mpg. That is low isn't it? Even for driving very hard throughout the entire tank? __________________ 1999 CLK320 Blk/Blk H&R Springs Bilstein Shocks K&N Drop-in BBS RX 18x8 s-03's V-1 Hardwired

02-19-2003, 06:18 PM	#5
mdp c230k Super Member Join Date: Jan 2002 Location: Los Angeles Posts: 875 Drives: 2002 c230k	I drive very hard and get about 14 mpg over a whole tank! Be happy with 17 mpg. __________________ '02 6spd C230K in Bril Silver w/C2, Eibach springs and sways. R1 Concepts Drilled/Slotted rotors F&R.

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