I have a 91 305 TPI Auto
When in neautral, wether warm or cold, if I rev the engine I get a slight backfire under deceleration. Its just two quiet, but noticeable pops.

When driving if I down shift to 2 or 1 I can hear it back fire aswell. It's nothing loud, but just wondering if its a problem, and maybe can be part of the reason to my suckish fuel mileage.

The car drives fine though.

Is this normal, or am I running rich?

 

When was the last time you changed the plugs and wires?

 

I have that too. But mine only does the pop when i use the engine to deaccelerate (shift from 4th to 3rd). I would say its normal. My bro in laws does the same thing. My plugs are 2 years old and have about 4,000 miles on them.

 

Another thing to check is your timing.

 

I just bought the car last month. I'll replace the plugs and wires this weekend and ill see if that helps. If not ill check the timing.

This question isn't threadworthy, but my 305 will almost scare me when I'm driving alone, but with a 200lb passenger it is alot slower. I go from about a 6-7 sec 0-60 to about a 9-10sec. With my v6 cherokee I couldn't tell when additional weight was in the car.

Does everyone's stock 305 do that, or maybe I'm missing out on a little power.