Engine problems

I have a 2000 Ford Windstar and the engine is making a noise that is simular to a noise of a sawing machine. The engine light is on and the noise is louder when the engine is cold. From time to time just after starting the car , the Rpms will go up/down and the car chocks. Went to several places for diagnoses and never could get 2 mechanics to agree on what the problem is.



Need some help

Thank you.

Autozone & other parts stores will read the codes for free. Write them down & post them here. Others can diagnose it from there.