When I turn my a.c the rpm drops, engine shakes violently and rpm goes up and down about 3 times. The car is absolutely dead in acceleration and when I come to a stop or go in reverse the car shutters and starts knocking and turns off. I have replaced spark plugs and injectors and new fuel pump. Could it be a bad a/c clutch or a dirty maf sensor( sensor is working because when i unplug it while car is running car turns off) or a idle control valve?
The a/c system has an idle up function and that should be checked. If the idle up function is not working properly, when you turn on the a/c the engine will bog down. You are also describing overall poor engine performance though, poor enough that I suspect other engine management issues, even if the idle up function were found to be faulty. The MAF sensor can be a cause and thus should be evaluated using a real time scan tool but there are quite a few additional causes of the poor acceleration that should be checked out as well because multiple, coincident faults often exist. A few of these other causes are vacuum leaks, a defective throttle position sensor and a defective idle air control valve. To get the underlying cause of the problem pinpointed and resolved, you can request an engine diagnostic for slow acceleration and the responding certified mechanic will get this taken care of for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.
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