I have a 1992 SE and it ran fine all winter, with the exception of the starter and alternator and battery. I replaced those during the winter.

Here'* the problem - Now that its heating up outside when my car is warmed up it decides to stall causing acceleration problems where i hit the gas and it won't accelerate after pumping the gas pedal i get some acceleration again but not full and sometimes it will just die.
Like i said it runs fine until it heats up fully then when i was sitting at a stop light it idled fine (a little rough) then i hit the accelerator and it died after moving forward a little bit. Oh and the oil pressure drops before it dies!
What could be causing this!?

BACKGROUND ON THE CAR AND WHAT I HAVE DONE SO FAR:
it has 198,000 miles on it
the catlyic converter has been cut off
fuel filter by-passed
and my fuel pressure is fine according to a mechanic

I have replaced the spark plugs(the previous ones were gapped at .80 and need to be at .60 and haven't been replaced in over 2 years)
I replaced the air filter (the other one was really bad)
I topped off my fluids
and my radiator is good so its not overheating
I just did a fuel injector cleaner treatment

What else should i test and do!?

btw No check engine light is on!

Check and clean your MAF. Then test your TPS/throttle position sensor.

Throttle position sensor TPS test
MAF sensor cleaning

update:

i just replaced the o2 sensor
cleaned the maf and throttle body and i'm still getting the idle that drops after the car heats up.

i'm going to check the tps when i get a chance today or tomorrow i'll let you know if that works.

Thanks