When I pulled the codes for the 300SL, I got O2 sensor and CPS. I decided to start with the CPS. Torx bolt out, minor inconvenience with a lot of extensions. Everyone makes it sound like you just pull it out and replace it like a light bulb. That wasn't happening. Tried needle nose vice grips and it still doesn't want to move. Put the bolt back in and decided to work on the O2 sensor. Bottom line there was drop the exhaust and take a torch to it.

After driving it and sheepishly realizing that my hopes that it only needed an O2 sensor were toast, I am back to needing to get the CPS out. I hosed it down with PB Blaster the first time and will try it again before I give up but this has been the year for getting my ass kicked on maintenance. Are there any pro tricks which work here, or is this one of those things best left to someone who has done it a few times?

Some background since this has dragged on for most of the year...this car won't pass emissions because its running rich. Idle speed is not stable on startup, it stumbles driving up a hill cold, and it dies when decelerating to a stop when warm. It has a new distributor cap, rotor, backing plate, a 129 fuel distributor/EHA/potentiometer because the old one was for a 124, temperature sensor, all new copper/brass fuses, all new vacuum hoses, new injector o-rings and housings, new O2 sensor. I got new plugs but the old ones are the same part number and looked almost as new as the replacements I ordered. I have a new coil for it but thought I would take care of the items throwing codes first. I hosed out the ICV with carb cleaner. I have not checked the codes since changing the O2 sensor.

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1988 300E
1993 300SL
1994 540i

If I have a problem with my Mercedes, I go to MercedesShop. If I have a problem with my BMW, I go to BimmerNut.
If I have a probem with my Dell, I reboot it. I was an engineer for them for 10 years and we blamed everything on Microsoft.