Backfiring???

[SI3G3]

Ok, don't know if this is up already, but w/e.

I have a '95 Nissan 240SX Auto. Now, here is the thing. Whenever I decelerate at a certain point (over 100 km per hour) when I get to 80kph and my tach is at 1800rpm, i'll hear a backfire sound (plomp plomp plomp), and it will only happen at that point. Also if I accelerate slow like, it'll kinda like hiccup (buurrrrrrrBURMMMrrrrrrmmmmm), like. I have a KA24DE motor with 167K, HKS short ram, and some generic 2-3" exhaust. I'll be getting a engine rebuild early 2009.

I'm told that the backfire is normal from one person, that it's the exhaust from another, i'm just lost now.

Is this normal for 240SX to backfire like that? can it handle a 3" exhaust, or could it be something fuel and engine related?

I'm open to any suggestions, and thanks for your consideration

[assassin7420]

IF its coming from the exhaust its not backfire, Its after fire. Back fire is out the intake.

If its a wide open exhaust with no cat or resonator, Then yes it will pop a little.

As for running a 3 inch exhaust on an N/a KA24... Pointless. Go with a 2.5