Running rough has nothing to do with coolant temp sender:thumbsup:
When was the last time ur car had a service? Could be ur injectors are clogged up, bad batch of fuel etc........
replace yoru fuel filter next to the tank. and clean your filter, but ls1's are common to run a little rough when they could but once they heat up they seem to go ok
Had the injectors cleaned only 10k ago and replaced the fuel filter at the same time, hopefully its only a bad batch of fuel. However when it runs rough when cold it also has a big flat spot down low once you get past that it drives ok.