some engine problems

[Night Rider]

Well i have a 92 twin cam 240sx se not a bad car but after i get it i throw a few parts on it. Thing big i have a 3' catback with the stock converter and a set of 4-2-1 header and a cold air intake and a walbro 255lrh fuel pump everything else is stock. My problem is when i run my air or heat for a well and trun it off the rpm drop to the point were the motor was to stop but when i trun it back on it run strong. i was thinking maybe the throttle was loose i play around with it and it was good for a well but start doing it again. I starting to think it maybe the air/fuel ratio but i dont know because i dont have a gauge i also so think it maybe my compression but again i dont know. I also think it could be my fuel injectors and i think that my injectors can't keep up with my fuel pump. So if anyone can help out on this it would be great like i said this a great car and i would just like to fixs this problem and move on to a new project.
Modified by Night Rider at 10:17 AM 12/14/2008

[Airmanspecial]

check your charging system, your heater/ac takes a load to run...if that load drops and your system cant recover, it could take som jiuce of your ignitionsystem......sounds wierd...see how much voltage you get across youre battery while the enginse running, should be around 13.4 ish.to 14.7..ish, if its around 12...your alternator is gettin weak

[Night Rider]

thanks i will look into that.