fbody3.8

i bought a 99 Camaro with the 3.8 a few weeks ago, couldnt stay running to save its life. although it would have periods of 15 sec. all the way up to a minute of perfect idling. if i was to give it throttle to keep it running, once i let off the gas, it would backfire out of the tail pipe, i found it was misfiring on 3&6. so i flopped coils around to try and chase it. and strangely just by flopping the coils around the misfire went away, no code anymore (previous code p0330). Has compression, has proper fuel pressure. the other day the check engine light came on with the same code but i couldnt feel a misfire (was still drive able) felt like it ran smooth, i heard that the coolant temp sensor could have possibly played a big role in that problem, (since it tells computer what to change timing to) looks like its never been changed, and dirty. the cooling fans also would not come on no matter what. gauge read that engine was at 210, but scan tool read it was at 225. the cooling fans only came on if i unplugged the coolant temp sensor. so i replaced the sensor, has anyone else had this issue? waiting to see results of if i fixed it or not. what can i do to fix it, and what have you found it to be? crank sensor, cam sensor, throttle body, TPS sensor have all been replaced as well as the ICM and 1 of the coils.