Hi everyone, let me thank you all ahead of time for having a great forum with lots of good information. My 2003 accent has been having problems the last 2-3 years with randomly not starting in the winter. The Hyundai dealership and 2-3 mechanics were unable to determine what was causing it, and as spring came, the problem resolved each year.

This year I found this forum and through a lot of searching and reading posts, I replaced the main relay and the crankshaft position sensor. The car no longer had the random problem of not starting, but now has another problem. It runs terribly. Ever since I put in the new crankshaft position sensor, the car is three times as loud and sounds absolutely horrible - while having a very rough idle and poor acceleration. It occasionally throws a code relating to the sensor (I wrote it down but didn't bring it to the office).

Does the sensor have to be calibrated or anything like that? After the first code, I pulled it out and found a lot of wet residue on it that I didn't remember seeing on the last one. Also, as I removed the first one, there was an o-ring that was blocking the sensor location that I assumed was from the previous sensor. It was badly mangled so I pulled it out and put then new sensor and o-ring in. As I look at the old sensor, it still has an o-ring on it.

I checked with the dealership and they said that the only o-ring is the one that should be on the sensor, which I have - is there anything else that the o-ring could have been?

Any reason the car would run like garbage with the new, or even old, crankshaft sensor? Is it just an easy swap where I put it in and plug it? The car went from running fine (but randomly not starting) to running poorly and throwing a crankshaft code. I've swapped the different sensors in, and verified that they're tightened to spec.

Thanks for any help in advance