Starting and, back firing issue

[panamarojo]

I have a 91 GSX and it takes about 10-15 secs to start, so long cranks, then while its warming up in idle, if i give it gas it will drop rpms, sometimes die or just drop rpms like it going to die then it will start reving up slowly. When I drive it when its not fully warmed, it it will make a very rapid popping noise out of my exhaust, in the middle range RPM's and then it will just run bad for the rest of the gear. DOes it in every gear. No CELs, I had either 11 or 22 so I replaced the O2 sensor and the coolant temp sensor to the ECM but it was from the junk yard and it helped a little. Any help?? I did a boost leak test and found a few leaks and sealed them up but still having an issue. When I took fuel rail off and pulled out an injector it came out easy, no pressure? could this be the issue? maybe fuel pressure regulator? or is the the throttle position sensor? becuase when I have the gas 1-2% down it runs ok, but very low boost. If I give it any gas it will start sputtin out the exhaust, kinda feels like a fuel cut or somthing.

 

[Jacie]

I'm almost having the same problem...