99 GT bad miss at 2000 rpm

Hey everyone i recently finished doing a tranny swap in my 99 gt i have a procharger D1sc on the car and a predator tuner. i put the procharger on the car approximately 4 years ago had fun with it and decided i wanted to change the way i put it to the pavement. so i ordered all the **** to swap from an automatic to a t56 i also put 3.90 gears in the rear. when i finished i realized i couldnt just swap ecu's because i have to get the manual ecu tuned for the procharger. so i drove the car around for a few weeks had alot of fun and it ran great it just threw codes for all the automatic trans **** not being there. then one morning i get in the car and get going down the road and the thing just starts intermitently spitting and sputtering at 2000 rpm on the dot. When this happens my air fuel ratio guage pins all the way down to rich. so i turned around went home and started checking everything 02 sensors, coilpacks, spark plugs and checked for exhaust leaks but none were an issue.
I spent a good 4 hours last night on this site seeing if anyone had any insight and found that there are hundreds of posts with people having the same problem but not one of the posts ever posted a solution to the problem and in all of the posts people say check your plugs coils etc. but it didnt fix the problem in any of them.

so i guess im wondering if my ecu quite possibly is going up due to the fact i am running an auto ecu in a now 6 speed car. i had planned on getting the car dyno tuned by jpc performance in MD but im not taking the trip accross the bridge till i find out what is causing this problem.

one thing that every post had in common was they all had a predator tuner is it possible that there are a bad batch of tuners out there. i reinstalled the tune to adjust the gear ratio on

so if anyone has any insight into what it may be please let me know

it is a misfire but only at 2000 rpms. my diagnotic tool was only showing the failure codes for the auto trans shift solenoids no misfire codes. the boots on the COPs were all intact and it idles fine and does not do it until 2000 rpms. if i give it enough throtle it will jump past 2000 and the rpms will rise normally with no miss

So for i was working on the car today and i took it for a spin and it was still missing and bucking driving. i had less than a quarter tank of gas so i gassed the car up and when i left the gas station with a full tank the car was no longer bucking it was smooth all the way when i accelerated. does anyone know why that made it stop bucking?

thanks man i guess ill keep tinkerin with it

I know its been a while but i just dropped my fuel tank and figured out that one of the fuel delivery lines in the tank on the fuel pump assembly had a hole in it so for anyone that has a similar problem in the future checking the lines on the pump would be a good place to look first. i was using my predators real time data feature and saw that my fuel pressure was dropping off to 4 psi. so that hole was causing it to happen when my fuel tank level got below the hole. im guessing the car would go into limp mode when the ecu realized it lost pressure i guess thats why my airfuel read rich.