I have been trying to get this UDP to work but it keeps throwing a code (random misfire in the first 1000 rpms) Some guys from another forum suggested swapping the reluctor rings. I did that and it got worse, it started to misfire really bad. I noticed the reluctor ring can move quite a bit and I have no way to center it so I swapped them back and put my stock pulley back on but now it's throwing a code. I got it centered much better but it still off a fraction of an inch and it had a misfire then. I pulled it back off and got it centered a little better but it had one midfire still (in 20 miles). We scanned it and it's the same as before (random misfire detected) and it keeps throwing a code. How critical is the placement of the ring? How do you get it perfectly centered again? If it's off even a tiny bit will it throw a code and cause a misfire? The better I got it centered the better it ran but still throws a code. BTW. I have given up on the UDP and returned it, I just want my car to run again with the stock pulley. Thanks for any help you can give.