Rough start up after sitting several days

[billfrank85]

01, 3.9, 90xxx miles, 5 speed

Did a complete tune up months ago when I got it. Plugs, wires, cap, rotor, ignition coil etc. Truck does not burn or leak any fluids at all.

Starts and fires right up perfectly when driven day to day. When starting after it sits for a week or more, it sounds like it's not hitting on every cylinder. It almost sounds like a diesel. Have to give it some revs for about 30 seconds then it goes away. The fact that I'm not missing any fluids tells me it couldn't possibly be the belly pan... Right? Only check engine code is for minor evap.

 

[jordanecoblasting]

Does your truck RPM not go up very high when you start it and do you have to hold the gas for 30 seconds or so or else it dies?

I had the exact same problem. My mechanic cleaned out the throttle body and changed the IAC and this fixed the problem. First he changed out the iac. No difference so he put the old one back on. Then he took the throttle body off and cleaned it. No change... Then he put the new IAC on again after having cleaned out the throttle body and this solved it.