I don't know whats wong! It seems the secondary injectors are not working. I checked the MAP sensor And the TPS both are working.
I checked the fuel pump and its okay. No vaccum leakage too. Please your support on that issue. I attached a video shows the back firing.

 

I'm at work so I cant look at the video right now . But are you back firing ? or bucking? what do your air fuel ratios say? what car is it?? year ? mods ?

 

The car is 93 rx7 fd. Yes, it's bucking and making backfire after releas the pedal. The plugs shows the mixture is rich. I checked the TPS again and I notice that fuel pump relay click while the throttle opend about 1/4 and start to clicking like crazy before the throttle fully opend. I checked the 3F and 3G voltage on the ECU as the service manual shows. The 3G always giving 5V in all throttle opening stage, but the 3F gives from 0.4 to 1 volts at fully closed, 1.5V closed to open and 4-5V at fully opened. I am not sure if the issue belong to the TPS

 

do you have a wideband ?

 

No. I haven't

 

I already installed a wideband sensor. See the Air/Fuel ratio start from 12.6 until the engine dead.