Hey everyone, I get around 170 miles to the full tank, I am running EXTREMELY rich, a lot of backfiring which I can tell is due to richness, what should I look at, plugs were changed 4,000 miles ago, no check engine light is on for any codes, could it be the o2 sensor?

Any reply would be great!

Thanks!

 

what are you mods?
Did this just start or has it always been like this?
How many miles on your engine?

 

20,000 on engine, downpipe and catback only mods! Pretty much always been like this!

 

Add a midpipe and an intake to it and u be running lean

 

Yes, could be the O2 sensor...

However, it's hard to say what "a lot of backfiring" really is... Backfiring will be normal when you remove the pre-cat, and "a lot" is relative.

So it's possible what you are now seeing is normal...

As far as gas mileage, do you have any highway miles in that 170? If not, then that's about right.

 

yeah, like mahjik says, change the O2 sensor.
also, you should do it anyway, but go ahead and do the common stuff like clean the air filter, fuel filter, maybe even plug wires (in case someone used old plug wires with the new engine)
then at least you have a base line to start with for diagnosis purposes.