[Tanked]

Just turn up the idle and see if that fixes it...although it might also need a tune up if the RPM's fluctuate that much.

both MPFI and DPFI setups have an adjustment screw for idle, its very easy. for DPFI, its under the intake air hose, where it leads into the DPFI air chamber, and for MPFI, I think its on the throttle body, on the side facing towards the rear of the car.