Hey guys, I've had this problem for about 2 months now on my 00' V6 4.0L. Everytime I go to start it, it either stalls after it turns over or it starts but the rpms drop and the power when driving is just not there anymore. I just got done replacing the fuel pump and fuel filter today as well as going over all vacuum lines and possible bad battery grounds. There is white smoke coming from the exhaust but I'm really hoping its not a blown head gasket, do you guys have any other ideas? Shes got about 125k on her. Also lately I've been hearing a sound coming from the engine that almost sounds like a supercharger when I give it gas while driving.

 

white smoke means probably a head gasget...

whining like a supercharger? not sure man...

 

When I start it, it starts up but then it sounds like it gonna die cause the idle is so low, and it'll sit there and sputter for 10-15 seconds then it'll rev up to a normal idle

 

what about a bad IAC valve?

 

could cause the symptom, although usually a bad IAC, the valve will be stuck in any position, and the idle won't come back up on it's own... wouldn't hurt to clean it anyways though, throttle body cleaner, and a bunch of q-tips, clean the throttle body it's self while you are at it, making sure to get the backside of the butterfly valve,

 

Well it was a bad IAC valve that was causing the starting problem, changed it out, starts like a champ now