you can buy the entire tension assembly or just the pulley, which i did. there is an identical looking idler pulley that could be the problem as well, its a toss up. they ARE different.
i operated on the concept that if you have a spare, youll never need it! and stashed it in the back door. when i traded the 07 i took it back for credit, put the 15 bucks in the tank

oh,at autozone,tell them its a chevy colo 3.7

 

I think you guys are assuming I can replace this on my own ? Although I am no mechanic and do not do much around the cars alone, I can do a bit of custom work and with a little guidance I can be pretty handy. Is there any pics or manuals I can look at to get this done, or is it that simple one can do without any guidance?

 

I just replaced the spark plugs at 100k miles and our truck is idling like a (5-cylinder) dream again.

(My maintenance tip for these engines is to pull, regap, and reinstall the plugs at 50k mile intervals or replace with new plugs every 75k miles for optimum idle quality and drivability.)