1996 Acura TL 2.5L Rough Idle and Misfire.
I have a 1996 Acura TL 2.5L with 260,000 miles on it. I have been trying to diagnose what is wrong with the car ever since it had weak acceleration on the highway and trouble starting/rough idling about 5 months ago. I eventually took the car to a shop and they said that the catalytic converter and one of the 02 sensors was bad on the car. After those parts were replaced the car intermittently still has starting issues, lacks power, and it still rough idles but not as badly. As I was driving the car home from the shop it threw a P0300 random misfire code. The car cranks but does not usually start until I put my foot on the gas pedal (sometimes white smoke comes out the muffler). The RPM gauge jumps rapidly and sometimes the car stalls intermittently after I let my foot off the gas pedal. Also during deceleration I sometimes hear an odd noise coming from around the IAC, sounds like air is being expelled although I am not entirely sure. I recently rechecked the iridium spark plugs that I replaced and found that they are full of black carbon deposits on the ends. So far I have replaced the spark plugs, spark plug wires, fuel injectors, fuel filter, engine coolant temp sensor, idle air control valve, fast idle control valve, and the catalytic converter, one of the 02 sensors (I have also cleaned the throttle body). Any ideas on what could cause these issues? I would really like to save this car if it is at all possible. Thanks in advance.