Bout 9 months ago went to to LA from Sacramento on the way back the car would not go faster than 30mph would have to press gas all the way down to get it going that fast...took time to replace the cat had one from a 92 5.0 tbi caprice that I stuck on there just so it wouldnt make so much noise...finally took my car too a muffler shop to get a new cat...they installed a dynamax cat and today after about 2 months with the new cat it does the same thing as it did when I was coming back from LA so my question is it the cat again or does anyone think it can be something else thanks fore reading and any info