start with the simple things first. you said you washed the engine. pull the coil leads and chk to make sure they're not damp or wet. also, chk the visible sensor connections to make sure water didn't get in them either. might be a good idea to clean the contacts of all while you have them apart. then at least you can start to rule things out cheaply.

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"the simplest answer is usually the correct answer"

1991 190e, 2.6 (helga)
91,000 mi