Looks like the Jetronic brain is going haywire with the data it is receiving.

Pull the plug off the EHA and disconnect the O2 sensor. This will run the car in open loop without any electronic assistance. Does the problem still occur or does the car fail to run?

Also double check your resistance of the temp sensor on the head is within spec both cold and warm.

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2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k

I did check the resistance of the 4 prong black coolant temp sensor after engine is warmed up (> 80C). it reads 230ohms across one set of terminals and 215ohms across the other. I dont think this discrepancy is large enough to cause error, but it is within the spec



I will try to cause open loop condition by disconnecting O2 sensor on my drive home from work. I cannot access EHA so easily without removing airbox.