I ahve replaced EGR VALVE. Plugs and wires, gas filter and transmission fluid. Car is hesitating and is hard to move, when accelaerating there is a loud whistle noise, one place tells me it's the catalytic, one place tells me its the transmission, bought the catalytic but do not want to install if that is not the problem, please help !
You probably have a vacuum leak. I usually take a piece of thread and drag it around mating surfaces, e.g. intake manifold to throttle body, to see if it sucked towards any mating surfaces. Of course look for bad hoses.