I just want to jump in here and caution anyone who uses a pressure washer to clean their engine - at least for those of us with the V8s anyway. I always assumed that as long as I kept the pressure away so that nothing was directly blasted, it wouldn't cause any problems. BUT, I rinsed my engine bay with a pressure washer on Thursday, and on Sunday I got a check engine light for a defective knock sensor. My research since then shows that apparently when you get that much water in there, it can sit below the intake manifold and corrode the knock sensors. A lot of the cases of bad knock sensors (P0332 code - only the rear knock sensor ever seems to get water damage) seem to happen a couple of days after the engine bay is washed. Sometimes it goes away, sometimes it doesn't. If my problem doesn't go away once its had a chance to dry, I'll have to replace both knock sensors and the wiring harness because I don't want to have to remove the intake again if the other one fails. The cost in that case would be about $200-$250 plus about 3 hours worth of labor... that adds up to about $500 or more total if you have a shop do it (at least in my area).

Anyway, after all that, what I'm trying to say is just be sure to wash your engine bay carefully.