2000 Mitsubishi Eclipse RPM's

The rpm's on the vehicle are un to 2000 the car Came for service replaced Spark plugs, filters, clean injectors and throtle, recomended timing belt and proceeded with compete service, water pump, belts and tentioners. Parts weren't available so car was siting for a mont now everything is installed timing marks are correct but the rpm's won't seatle I tried resetting PCM with scanner and by disconnecting battery, checked tps and cts signal, no vacuum leaks, hoses that run warm coolant through throttle are warm on both sides, air by pass screw on throttle is all The way in and if turned out wards rpm's get higher. Scaner shows idle motor steps aboud 34 sometimes will go to cero with A/C on, after driving 15 miles rpm's went down but one's the switch was cycled rpm's went 1500 again