Hello,

I have a 1988 300E W124 and I took it in for service the other day. My
mechanic lent me his 86 300E as a courtesy car. When I drove it, I realize
that my 88 300E is so much slower than my mechanic's 86. I bought the car
brand new back in 1988 and I guess my car is getting slower (slowly)
everyday, so I don't even notice that my car is so slow.

Specifically, the acceleration of my car from stop is so much slower than
his car. What could be wrong with my car? My car has 245,000 kms on it and
have never done a valve job yet. Could this be the problem? Or could one
or more of the cylinders doesn't have enough compression? I guess if this is the case, then the engine will vibrate like crazy, right? However, my engine is smooth as silk at all rpm's. What else could
be wrong?

Please advise. Thank you in advance.

There were changes made from 86 to 88. The 86's were tuned a little hotter in most cases. Mine was fassst. I drove it ro over 200,0000 miles and it would still out run most of the newer 300 e's. I would let it be if you are happy with yours.

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Benzmac:
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

Thanks for your response....I've also heard that a bad O2 sensor can cause a loss of power? I still haven't replaced mine yet (since the car was new)....i.e. the O2 sensor has been used for 245,000 kms!! (It's supposed to be changed at 96,000 kms, but I didn't change it.) Could the O2 sensor be the problem? Also, can someone please give some pointers on how to replace it? I know it's made by Bosch...but the MB dealer wants CDN$150+labor. I've heard that the 1990 Ford Mustang V8 uses the same O2 sensor and someone has actually used it in an MB and it worked flawlessly. Can someone verify this?

Thanks in advance.

Usually the only diffrence in the the sensor is the connector. Bosch makes universal heated o2s with 3 or 4 wires. I'm pretty sure yours has 3. When replacing it, make sure the wires are soldered and shrink-wrapped. The final step I suggest is to moniter the o2 signal with a lab scope and go for a drive to make sure it is switching in which case the o2 is working. The o2 costs around 75$ cdn and should work.

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Chris Muc
Auto mechanic
'87 300E 325,000 km