Car developed a miss- on 1997 Mercedes-Benz S320

I washed off the engine (cold) with the garden hose after replacing the brake pads and now it runs rough and the "check engine" light is on. I dried all electrical connections including removing,cleaning,and re-gapping the plugs. Blew air through the coil packs also. Used di-electric grease,etc. Still has a miss,can you help me? Thank You,Randy

Asked by for the 1997 Mercedes-Benz S320
Have the codes rear out, that may help direct you to where the problem is. It may go without saying, but washing an engine with water is not a good idea!
3 more answers
I have a 96 s32o and I have that kind of problem; rough engine run. this happens when i exceed the 3.5K rpm during acceleration and the'check engine'light turns on. I get a PO3 missfire on the diagnostic report.

a quick fix that i do is to turn off the engine and restart. the check engine light remains but the rough run goes away. to turn off the check engine light, i simply erase the report from the car's computer w the OBD tool.

I hope this helps.

As for this problem, is there anybody who can tell me why this is happening?


The same thing happened to me and I couldn' figure it out. I finally found a similar post. I there was water in my spark plug wells. I had to remove the water with paper towel and dry out the spark plug well with air. Then I replaced the plugs and the car is running better now than before the problem. The spark plugs on the s320 are located under the plastic sheild in the middle of the engine. You will need to remove the air intake manifold first to get to the spakr plugs. Remove the throttle wire then remove the items.
Did you happen to check to see if your timing is correct, and if you have a faulty condenser ignition?