hey alright thanks for the info!

i always listen to the engine when i drive and i haven't heard anything anomalous pointing to the timing chaing, during startup cold/warm and when its been running for awhile. During a cold startup, there is a high whine (but not high rpm) for about 1 min as the engine warms up which has been with me since i bought it at 40K and I believe that is a normal thing.

interesting is that a mercedes parts website (can't remember the name atm) says the timing chain can break and recommend replacing it...that's what got me to getting curious and posting this thread.

ever since i replaced the wiring harnesses, the car has performed much better with better acceleration and it feels like a different car. naturally the harness got replaced when the check engine light came on and the codes poured out knock sensor, O2 sensor etc etc...but none of these have triggered the light again...i think its only a matter of time for the 02 sensor seeing how its getting close to 100K. the dealer also recommended replacing the charcoal cannister valve but said it wasn't immediately necessary. I don't recall replacing that one since I got the car at 40K and I do see it to be a seperately serviceable schedule every 60K or so?

now to get that warm engine start symptom erased...got the OVP on order so crossing my fingers.

do you guys think the spark plug wires/boots need inspection too?