I got my truck back from the shop and it sounds really sexy, but my idle is really funky. I have pacesetters longtubes, magnaflow highflo cats, and a si/do catback for reference. the rpms will drop real low to 3-500 range and climb back up every now and then, and the downshifts has a real low drop to it to. It seems to be getting better the more i drive it and it isnt throwing any codes. Do you guys think that the computer is just not adjusted to the airflow yet?

 

You need custom tuned after adding longtubes. Thats your problem.