Ok after long drives or hard driving after a while screaching noises that are very hard to describe are coming from my exhaust. It only lasts maybe a second and then is gone, could this mean my cats are clogged???

 

I bet you that noise is from the heat shileds around the muffler. Ever since I had to take them off to replace my wifes fuel pump after going up a long hill or drivbing it hard you get this screech sound.

I guess it is the way the heat shileds fit up to one another, when it gets hot, they expand? and rattle and screech next to each other.

I tried tightning bolts on the heat shiled one time at night, and it helped a little.

good luck

jason