hello thirdgen. 92 3.1 bird. i just replaced the fuel pump which wasn't fun. then bypassed the vats system. after these two things. i am getting nasty RPM spikes when i reach 2,000 rpms. and it also sounds like backfires/misfires when i give it gas during the rpm spikes.and just an hour ago i had trouble starting. when i was cranking, rmp meter would jump also. any ideas?
thank you in advanced for feedback.

iv replaced all major sensors.

I assume you didnt have problems before, correct? Did you do the fuel pump and the VATS at the same time before you started the car or did you do one and then later do the other?

Does the car start now and only run rough at 2000rpm's or does it just crank? If it does crank, does it sputter like it wants to start or just crank?

no i didnt have this problem before, only issues i had was lack of fuel, low fuel pressure. whats why i changed the pump. also because the pump went out. after installing the pump. the VATs problem kicked in. i tried cranking after i put in the new pump. got nothing. that when i found out i had the VATS problem. in a way i did it at the same time just a day after. pump one day, VATS next day.

when cold, the car fires up good. first crank. when the car get hot, after iv parked and leave the car. when i come back it will either crank or it doesn't when it doesn't that is when i see the RPM meter spike when i crank. Now when i am driving. once the RPMs hit 2k the meter spikes. lack of power and i feel in the pedal that the car is giving off little misfires or something. in sync with the spiking of the RPM meter. i took a short video of it. but i cant upload it.
thank you for your feedback