95 camaro engine problem

RIght, i have a 3.4litre 95. It idols ruff excelerates ruff and missfires normally when it down shifts to speed up or when going up hills. Ive changed the spark plugs wire's and coils, fuel filter, and fuel pump. Ive also ran several fuel injector cleaners through it. Problem is still not fixed :(. Its not throwing any engine codes either, even though for some reason my early model 95 has a OBD 2 when im constantly told they didnt install those until 96 heh. funny thing is when its cold outside the car run's nice and smooth, but will still misfire a little if i try and floor it. Any suggestions??? PLEASE HELP!!