Have you done anything to tune the car? My 1st guess would be the FPR. Is it a 1:1 or something higher? You may also want to check to see if the diaphram (SP?) is ripped inside the FPR. What size injectors do you have and how old/used are they? Have you checked for fuel leaks? Remember my car when we were changing the motor mounts. It might not be as bad as mine was but you may have a little slit somewhere.

Also pull the CEL code. Since yours turned on before from a different issue, it may still be adding codes stating you are running to rich or lean since then and you wont know it.