M103/190E Twitching Idle and Error Code 29

[John5788]

Hello,

It has gotten quite cold here in socal and my 1993 190E 2.6 is having some odd problems.

I noticed just starting today after work that my car doesnt idle anymore. The tachometer twitches like crazy from 500-1500 rpm, engine feels rough, and I hear an odd clicking noise coming from EZL/ABS area. Engine will also stall on its own randomly in this state.

I replaced the OVP with a spare that I had (first instinct) and the problem still exists.

I checked the blink codes and I am getting error code 29:

29   Difference In Coolant Temperatures Between CIS-E Control Unit and EZL Ignition Control Unit

I am about to swap the ECU out for a spare that I have. I am going to leave the battery unplugged over night. Can anyone else suggest other places to look?

The coolant temperature sensors (black 4 prong and blue 1 prong) are new from dealer as of august 2010. Interior cluster temperature gauge does not seem abnormal.