2001 Tiburon no RPMs
 

I have a 2001 that will not rev past 3000 RPM. Occasionally I get a misfire number two. I have change plugs and wires. Switched injectors. When cleared it does not return unless I hold petal to floor. RPMs go to 3000 and then fall until engine almost dies. I have also replace the throttle position sensor as that was a code until replaced. Vehicle has 127,000 miles and is an automatic. Any clues what the issue is? Thinking maybe the converter may be plugged. If plugged converter would it throw a code? Fuel pressure? Wouldn't that also throw a code?
Note.:starts right up, runs smooth, just will not rev. Sounds like it is bogging.