Crank position sensor
Ended up driving through torrential rain in South Florida on vacation Saturday night, and a LOT of standing water. Just at the end of the storm the car started bucking really badly, and I thought it was going to stall completely. First thing I thought was I got water through the intake and I'm screwed, but the car keeps chugging along (which was greatly appreciated, since I was in the middle of Everglades nowhere) and actually drives a little better as I pick up speed. No SES or service vehicle lights illuminated. I make it into a gas station parking lot with some lights and give everything the once over, nothing obvious broken or leaking so I keep on going. I notice that at cruising speed the car is generally driving horribly and can barely make a gear change, but in OD on the Interstate it runs like a champ. Also when the car starts bucking, I also lose the tachometer completely for a little while. Once I settle in the hotel parking lot I use the Interceptor to scan for any codes, and I see I P0101 (a predictive MAF value) and P0336 (crank position sensor). No misfires recorded. Checking Tech and some OBD sites I found the troubleshooting guides, cleared the codes, ran through the flowsheets and the next day I'm on my way home again. Same problems Sunday and Monday -- horrible cruising manners but great highway driveability (some stuttering, nothing really bad though). I limped home the whole way from Florida like that. It seems to be worst from 35-60 MPH. All of the flowsheets lead me back to some physical damage to the CKP, so I'm going to replace it and see if it helps. Any other suggestions or ideas?
But....That is exactly what a Crank Shaft Position sensor does when its failing.

