Hyundai Repair: Rough idling,bad emission and speed, transmission control module, hyundais

Question
I car presently has a rough idling with bad emmission.I had the plugs,MAF and fuel pump changed but still no difference.Now i throttle hard to get the car moving at all.When i put on the A/C it shakes the engine rigourously,The mechanic said it may be a problem with my ECM?..can this be true

Answer
It's of course possible the problem is with your ECM, but this is very rare on Hyundais.  Based on your description, it sounds like the engine is misfiring.  If that's the case, the check engine lamp should normally be illuminated or flashing.  If it is, you should begin by reading the diagnostic trouble codes in your ECM and TCM (transmission control module).