There are a few possibilities;
The Idle Air control valve could be sticking. If the idle gets worse when you turn on the A/C or other accessories, this is probably the culprit.
The fuel sytem could be dirty. Run a can or two of BG44K or SEA FOAM. These are the two best fuel system cleaners on the market.
Replace the components that the manufacturer suggests as part of routine maintenance for your tuck.
If you have never replaced the O2 sensor, that would be the next step if the others do not solve the problem.
Wednesday, March 2nd, 2011 AT 8:07 AM