91 bad cold start, rough idle, underpowered

A really long cold start, may take 3-4 attempts and gas pedal to start up. Next start will be perfect. Plus ocassionally rough idle around 1000 rpm with vibrations. Plus the car is not as powerful as it used to be. The code reader said something about too much fuel injection. Fuel pressure is high. They cleaned IAC, cleaned injectors, replaced air filter - helped with power a bit but still runs roughly on idle and doesn't start well cold. Recently CHECK ENGINE light began appearing after 10 mins of run. Reappears nearly 10 mins after restart. Appears ocassionally. I guess there might be problems with fuel pressure controller but i don't know why they didn't replace it on the station.

have you had the throttle positioning sensor checked that might have something to do with it also. start running low grade gas in the explorers because for some reason on these newer ones the hight test gas makes the check engin light come on i belive it mess up the o2 sensors

what he ^ said. and check the o2 and is the cat clogged?