98 Durango Dash light problem

From : d

Q: you can do an exhaust pressure test to see if the cat is clogging up. also take a rubber mallet and give it a couple of whacks not too hard! and listen for any signs of internal looseness/rattles. there shouldnt be any. mike -- if at first you dont succeed youre not cut out for skydiving i had a complete new exhaust put on before the engine change last summer. i did notice a difference in the tq. the mechanic was not sure that it was the bearings making the noise because the rattle came and went. he asked me to have the exhaust checked. when i got it there the exhaust guy said there was definitely a problem. when he cut off the cat all the stuff fell out of it. there was noting left to the muffler. i did notice more engine power after that but the engine still needed to be changed. is there any way to check the cat without cutting it off i just bought a high-mileage dakota and was thinking of having a mechanic give it a once-over to identify any problems before they get worse. .