I have a 89 gxe auto. first problem is a high pitch sound when im driving and step on the gas hard to get car to down shift the car makes a high pitch sound around 2400 rpm. this always happens at this rpm as long as you try to get the car to downshift. if you shift through the gears yourself the car does not make this sound. i was able to go on the highway and hit 65 to 70
as long as you ease on the gas to get the car up to speed. The second problem is the car intermitenly stalls when car is at idle and after you come to a stop and let car idle after hearing the noise i mentioned.

ive noticed that this noise sounds like pressure build up in the engine. so i lossened the back part of the y pipe and noticed the the sound goes away much faster now. the cat is good because i took it from a goodcar so i know it not clogged.

any help would be appreciated
thanks maxima93gxe