Engine Performance problem
2003 Mitsubishi Eclipse 4 cyl Two Wheel Drive Manual 178000 miles
I purchased a 03' eclipse about 8 months ago. It had a blown engine, so I swapped it out with a engine from Ebay. Before I got the engine the person I bought the car from informed me that the engine I bought came out of a Automatic Eclipse. Mine is manual.
My car runs and drives great once it's warmed up. My problem is that if I start it when the engine is cold. The engine will immediatly rev up to 3000 rpm, and then idle down real slow. After about 20 minutes I get a P0421 code. I found that if I disconnect the air intake hose from the Mass air sensor. The car will start up, and Idle perfectly.
I've already replaced the Idle Air Control motor, and Mass Air Sensor.