Zsaint, sounds like you are running lean unless you give it full throttle whereas the TPS then enrichens the mixture. You need to do a full EFI diagnosis starting with fuel pressure (you have started to do that) and a vacuum system inspection, then electrical conections. Check the EFI bible and the FSM.

I agree that it sounds like your are running lean. Here is simple test you can do if you are not good with and ohm meter.

First turn up you idle to about 1800. Then disconnect the water temp sensor and it is the one with the black wires. the idle should drop back to about 900, and then take it for a ride and if it seems like it has power than I would looking real hard at the AFM. do not leave it set up like this because it will carbon foul the plugs.

I will start doing some checking on the EFI soon. Thanks for the help. I will give you the results so you can give me direction.