I have a 99 limited V6 4wd. I recently purchased an Airraid throttle body spacer and air intake kit along with a Borla exhaust kit. The problem is now the truck runs like crap. I have never had any problems before now the check engine light is on it idles up and down almost to the point of stalling. I contacted Airraid and they claim it can't be due to their product however, I am pretty certain it is something with air management. I wouldn't think the exhaust would do it. Does anyone have a Borla exhaust on a similar model because I am not real thrilled with the sound out of it either.