Good day everyone, I’m new here so Ill introduce myself. I joined this forum because im stumped over a issue with my 1989 240 GL sedan. Heres what happened:
I got home one day to realize my car had a check engine light. I checked the code and it was the one for the 02 sensor. While I was under there, I also noticed I needed a new brake master cylinder, so I went ahead and ordered a new sensor and master cylinder, including a new coil since It was something else on the bucket list.
The cars sits for about a week, and when I finally get my parts and install them, the car wakes up with this nasty surge in the idle! 🤯 I have a well rounded mechanical knowledge, So I went ahead and looked at all the possibilities and dealt with them…
I put the old coil back on… nope
I checked for vac leaks… nope
I cleaned out the throttle body and IAC valve… still surging.
I ended up trying to drive the car for a few minuets to see if there were any other issues, and it smoothed out a bit after that, but it still would surge every now and then if I were stopped for a bit. At least it drivable, but the surging worries me… You guys have any ideas?