Hey guys,

I'm not very good with engines, so i'll need some help with this one.
When i cold start my engine (3.0 V6 3VZE), the engine idle is fine, no problem here, but once i get the engine warmed up and and let it idle, the idle begins to bounce up and down. The idle bounce is not much but i'm pretty sure there's something wrong. Any ideas of what's wrong?

 

Check the throttle position sensor adjusment. If the ECU is not being told the throttle is closed, it will use the O2 sensor to adjust the fuel mixture and the idle speed will 'hunt' or fluctuate.

 

I also noticed that when i do start up the truck, it's kind of rough, would adjusting this (if this is the case) allow for a smoother startup?

 

idle speed and timing are set with the engine warm, not cold

 

Your idle is to high. This could be from air in the coolent, vacuum leak or just out of adjustment.

 

also could be fuel filter!

 

thanks guys, earlier the weather wasn't cooperating with me, so hopefully soon i will be able to diagnose the problem.