Alright sounds as if you may one of two common problems. First, it may be due to fuel 'flow,' probably insufficeint from a failing fuel pump or plugged pump screen. To correctly identify this condition, you have to measure fuel flow from the test port with a good guage connection. The pressure can be good and the flow still insufficient. You should deliever approx. 1/2 pint within 30 seconds, at the rail.

Now, with the fuel flow out of the way. I really believe you have a malfunctioning MAF sensor. First, remove it from the intake, and look down inside it with a brite flashlite. You should see a couple of thin 'film' wires, that become dirty and will cause this. They need to be sprayed down with throtle body cleaner or MAF sensor cleaner, then dried. They should look close to clear after the cleaning. This cleaning should be done first, but the MAF might more likely be bad. It requires a lab scope to diagnose, if you have access to one, I can give you instructions on testing it. Also, if you use any type of aftermarket air cleaner, that is 'oiled,' this can lead to MAF failure as well.

Bogging down, and backfiring are to common symptoms of a lean fuel mixture condition. Restricted fuel to the engine and sensors such as the MAF, have a large influence on how fuel enters the combustion chamber.

-Rip