Hello everyone, all help is greatly appreciated. I am having a problem with my 2000 Mazda MPV. The check engine light is on and the obd 2 codes are PO740 and P1512. I have a crackle sound when I start the engine and a hissing sound before it shifts especially when the engine is cold. If I replace the intake manifold and torque converter, will this repair the problem? Any advise?Thanks to all that respond-Lina

 

You should first isolate the crackling sound as determining its exact location will help a lot in diagnosing your problem. I am also suspecting that your engine rods are knocking.