Oh, hey I just remembered, the 2.5 were notorious in all models for collapsed/split vacuum hoses to the MAP sensor causing this kind of stuff. The MAP is on the firewall, or on the top of the motor, not sure which on yours. It is a little black box, rectangular and flat, about 3 inches by 1 inch by 1/2 inch thick, should have one 2 or 3 wire plug, and 1 rubber vacuum line going to it. Look at the bend in the line going to it carefully. If it is split, or spongy and easily piched closed, replace it. An incorrect reading due to poor vacuum will drive the ECM nuts.