[281SLEEPER2v]

my mustang is a 2000, long water pump, windsor motor..Ok so when i installed my cams and was putting my timing cover back on, it snapped at the bottom. there was a huge crack. so i found this guy that had a motor out of a 2000GT. i went to get the timing cover off of it. the pulleys on it were different. it went with the short water pump. and the belt tensioner was different. anyway the timing cover bolted right up to my motor, i had to swap water pumps as well. when i went to go get a belt, i asked for a 2004 belt since the timing cover used the short water pump(that was my guess). when i go to put the belt, the belt is waaaaaay too big. i did my research and it turns out the belt tensioner i put on now is from an early 4.6(96-98)meaning that the timing cover is also from an early 4.6

here is a pic of the belt tensioner on my car now..


My car runs fine but it only does one annoying thing. every time i brake as i decelerate with the car in neutral the cars rpm's just sputter and the the car dies....when the car is at a dead stop and i step on the brakes real hard the rpm's drop...ive gotten used to it, but i would really like to solve this problem. at first i thought it was cause of the cams but i realized it does it only when i step on the brakes. im wondering if it does this because its a different pulley set up or could there be another reason why its doing it...any suggestions and help will be greatly appreciated.