I have a 94 integra with a b20 swap and i've been noticing im probably getting 15-25 miles per gallon. I know this is not normal in a teg. My check engine light is on and my muffler makes a popping noise from here to there everytime i accelerate. Could it be that my o2 Sensors are bad or am i running to rich? I pour 93 by the way. Some advice or help would be greatly appreciated. Thanks

 

You are definitely running rich, take it to schucks/o'reilleys or something, they check codes for free. But it could be o2 sensor that's bad.

Is the ecu for a b20?
What else have you "swapped" to make this engine work?

Also, why 93? Unless its built/turbo'd, it will run just as good with regular than with premium. Better gas mileage as well....

 

Idk i'm just use to putting 93 but i literally dont know what else been swapped because i just bought the car literally a couple days ago

 

Figure out what the CEL error code is.

 

check the code(s). first and foremost. if it's a b20b1/4, that 93 may be doing more harm than good, since usdm b20b's have a terribly low compression ratio.

you may not necessarily be running rich. but it sounds like you aren't burning fuel adequately. the backfire is likely due to this. could be a number of reasons.
check your timing. but check those codes first. unburnt fuel in the exhaust stream will contaminate an o2 sensor quick, so if it hasn't already, it will.

-check code(s)
-check timing