Catylytic Convertor problems

Here is some more information. I think my problem with my cat heating up may be related to the fuel system. Although I am not getting any new fault codes I think the system is running rich. Also when I shift into neutral at stops(traffic light,stop sign) The RPM's quicky fall and the Engine becomes quiet for a few seconds like it is going to stall. It has only stalled once at a stop and it usually recovers RPM's after a few seconds of stopping. There is a strong gas fume odor around the engine compartment while it is idling. I replaced the ECTS going to the PCM with a brass tipped one,the one I replaced was cracked and this repair didnt help any. For about the last year ive been driving with the SES light coming on intermittently mostly it would come on while at stop lights or when driving for 15 minutes on the highway. I was receiving codes 26,32,and 45. I replaced the EGR solenoid,resetted the computer and have not gotten any new codes since. I also replaced another o2 sensor today. The car accellerates very poorly and I can hear a growling sound from the engine/exhaust when accellerating The car has 118,000 miles. Does this problem sound like a FUEL PRESSURE REGULATOR or LEAKY INJECTORS? The car starts up fine no hard starts at all. At first it was an intermittent problem that developed to a permanent problem over a 3 day period. After making 3 different trips in a day, a few weeks ago, it drove poor like this I shut the car off and 20 minutes later started it again and it drove fine. Then the next day I drove to a friends house and it drove fine but 30 minutes later when I drove home the driveability was poor. The next day I drove around the block and it drove good with good accelleration,but the 3rd day it drove poorly and has been that way ever since. The problem never arose while I was driving it always started between start ups.