Does the infamous cat rattle lead to any other potential issues? such as loss of power or anything else? I would assume if its clogged, but if its rattling is it the eqivalent of being clogged? if so, rattling or clogged being the same, would that cause loss of power, long cranking at random and sometimes a little stumble while starting, higher rpm losses etc. i konw if its clogged you can get all of those, but if its just rattling, maybe it is still causing a blockage too depending on how its resting inside? my car is running pefectly smooth, but i notice my power band is sometimes better and sometimes a bit off. i changed the crank sensor and have seen some improvement on the long crank, but sometimes the long crank still happens however its just not as long as it used to be. this morning on cold start up it was slightly longer, but no rattle right away. then rattle came about and once that happened i noticed a bit of a change in acelleration. my first tank the mpg was a mix of 150 miles on the freeway, and about 100 miles city driving and some idling/sitting....got about 18.2mpg.

cats are finicky, and some cars react differently. so on one of my old bmw e38s, it wouldnt allow the car to shift into overdrive, however i didnt really have much loss of power, in another e38 all the did was rattle and throw a code but i had no loss of power at all, at least most of the time, and another e38 i had it wouldnt let me rev over 3000rpm, and was a total sloth, cause misfires once i pushed it to 3k. not sure how these M113s react to any kind of cat issues. obviously i am going to take it and get the rear cats removed and just throw a straight pipe in their place regardless, but im just curious on the experiences of others.

 

Engine/Transmission mounts.