New person, hello all.
 

I have a 2005 Pontiac sunfire that I am doing mods to. Started out getting 380 miles per 14g tank of gas. After addition of K&N air filter, synthetic oil and high filtration oil filter bumped up to a whopping 420 MPT. Anyone else have suggestions on how to increase mileage?

I've gotta ask
 

Welcome to GasSavers...

I'm curious -- the mods that you've mentioned generally do not achieve that big of a jump in gas mileage. There may be some other variables at work...

Take a look at the thread in my sig to get an idea of what to try. They range from Mild to Wild...

Best FE,

-RH77

SunfireRaz -

Welcome to GS! Is that a manual or automatic transmission?

The welcome thread is a great place to start for investigating mods :

https://www.gassavers.org/showthread.php?t=4542

CarloSW2

Hello and welcome! There's a lot of good info here and lot's of great people!

sunfire got the 2.2l? lol that milleage is slightly less than my s-10 with the same engine. hehehe still very good tho.