The car hesitates (just slightly) on acceleration when winding out through the gears. It hesitates less with more load. Has just been tuned up, fuel App 25MPG, plugs burn almost white on the curve of the electrode and then light tan on the flat part. # four plug is a little darker (I replaced it, no change), 142,000 miles. Does this car have an ERG valve? They can get dirty can't they?

Have the o2 sensor checked, it is probably the original...Have the fuel mixture checked and reset after replacement.

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Benzmac:
Donnie Drummonds
1992 500E (very soon I hope
1981 280GE SWB
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

quote:

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Originally posted by Benzmac:
Have the o2 sensor checked, it is probably the original...Have the fuel mixture checked and reset after replacement.

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Thanks Benzmac, the O2 sensor is new, I also had a differencial pressure check across the catalytic converter and it is OK, I adjusted the air sensor plate at 1.5mm clearence between the sensor plate stop and the mixture control piston at the time of the O2 sensor replacement (2wks ago). At first car was hard to start. I adjusted the allen screw 1/4T CW and starting got better, maybe still a little hard.
I was trying to feel my way in on this mix adjustment. If I make another adjustment, I think 1/8-1/4TCW would be the direction. I watch the plugs after driving 1/2 tank or more after any adjustment.
Do you agree/disagree?
I do not hold you responsable for my stubornniss!! and penny pinching!!

Thanks again, Bill