The car seems to have most of the stumbling at part throttle under load, full throttle it runs better. At idle, it runs OK but at times u can hear it slightly backfire(real mild)

I don't think it's the cat because, the primaries on my headers are fine. I only got that rotten egg smell once and thats prob because the car was misfiring and not burning up the fuel(running real rich). The cats are pretty new, random techs.

As far as fuel pressure, it could be the problem BUT when I go WOT the car runs better the pump seems to be able to keep up.

I bought a new ignition system just because I believe it is MOST probably the cause, just because this started happening AFTER my water pump went out and the opti probably got soaked(like a month after i changed my pump, the car acted screwy). I figure that car already is 8 years old and has close to 90k on it, its about time for an opti anyway(I also upgraded to a better coil).

If this doesn't help, I'm going to check into the fuel side of things, starting with fuel pressure.
Thanks for the help so far, I feel good that I have a path to check now(ignition then fuel)
I guess if I still have problems and the fuel checks out, it has to be the cats huh?? If it is, I'll get an offroad pipe, remove smog, and run 02 sims.
Brian

 

well my car was able to still smoke the tires with 25psi which is way low,and at wide open throttle the car didn't seem to be struggling or lacking power but im sure it is with that little power... so don't dought the fuel side but what ever fixes the problem please let me know cause im having the same problem that your having...