Engine not running smooth

Hey guys , I recently made a post talking about how I’m having an issue with the engine not running correctly like it’s misfiring.

Since then I have change fuel filter, taken the fuel pump out and tested it, checked the ecu, checked the coil packs and checked for vacuum leaks

But I was recently looking through a forum talking about decats and I put in a decat myself but I just unplugged the wire which threw up a light but I thought wouldn’t effect the engine , however some people are saying that I need to make a loop on the sensor plug otherwise it could cause it to run bad, is this true and worth trying even tho mine is the 1992 tt model ?

Thanks