Bought it in April under the impression, "nothing was wrong with it" and knew right off the bat there was something wrong with it. Just no power and when you press the gas to take off it studders some times and when you try to pass someone on the highway or take off fast it won't shift at all. Acts like it couldn't figure out which gear to go into so it goes into neutral. When it does that the only thing that temporarily fixes it is to turn the vehicle off then back on. One time when I was driving on a gravel road up a mountain the wrench came on and there was a faint burning Smell and it eventually stopped going uphill and started rolling backwards. When driving on the highway and going over small hills it would act like it doesn't know what gear to shift into when it's supposed to downshift so it just jerks and keeps changing gears unsure which one to stop in. does ok if you drive slow like a granny and take off as slow as you can. I have rebuilt the transmission finding 2 bad clutch plates. Replaced the torque converter, valve body, and even the ecm thinking that it was damaged whenever the ignition coils were trashed. (I did replace all the sparkplugs and ignition coils when I replaced the ecm). It still runs like crap. I was reading on another forum about other people having similar problems who were told by other members that it might be a clogged or bad cat. Is that even a possibility?

 

I would suspect the vehicle computer should be picking up on a problem.
It would be a good move to have the computer checked for any history codes.
Because the limp mode problem gets reset when you turn the key off then back on tells us the problem occurs when the vehicle is moving.
There could be any number of reasons and the object is to find the problem causing the limp mode and protecting the rest of the vehicle components.
This type problem usually takes considerable time , tools and effort, but a good tech usually will manage to pin it down .

Even if it is a catalytic converter problem there is a cause and simply replacing a converter is only half the job.The reason needs to be found and corrected if that is found to be the problem.