fuel additives?

[Jim Matthews]

Properly inflated tires provide a noticeable improvement in my fuel economy.
I get near the same mpg out of my '03 Honda Odyssey which is considerably heavier than your Focus.

If you can keep a constant speed around the buggies, or coast to manage your speed, then your heat loss in braking will be reduced.
As you are well aware, the Focus has a sweet spot for fuel consumption which should be right around your travel speed on two lane roads.

Coast when you can, brake when you must, anticipate your speed changes or your mileage will go bust.

[Jason Roehl]

I had heard that much of the fuel injector cleaner out there was essentially kerosene with a small percentage of other solvents thrown in.

I haven't used FI cleaner in years now, with no fuel system problems. Gas today is pretty tightly controlled and very clean. I've never had any sort of contaminant come out the back (input) side of a fuel filter (an over-replaced part, IMHO).

But, gas is also highly variable from region to region, or city to city. Last I heard, there are 18 different formulations required by various AHJs around the country. Multiply that by the typical 3 octane ratings offered, and you have 54 different types of gasoline sold across the land.

[Bryan Morgan]

Talking to a BWM tech they re-bottle Red Line SL1 and sell it to you at twice the cost. He claims they use it because its the only stuff that actually works.

[Jim Rimmer]

The gasoline sold by the big names have all you need as far as additives. LOML got a new Honda Accord in 2007 that was supposed to get 25 to 30MPG. It wasn't doing well at all. She had been buying gas at the grocery store and the big box store. As an experiment, I asked her to buy only Shell gas for several tanks(any big name would work, Chevron, Exxon, Valero, but I had a Shell card that got me a 5% discount). After a few tanks of Shell the mileage increased 3-4 MPG. The grocery store and box store fuels are cheaper because they don't have the additives. (It is my understaning that the additives are put in at the tanker facility but don't accept that as fact.) It is worth it to me to switch to big name fuel. YMMV.

[curtis rosche]

i always use Hess, somehow i got 24 mpg on the way up from millersville to summerset, and i got 28.7 on the way back.
on the hilly roads while i was there, i got 19

[Jeff Bartley]

if you were looking at diesel there are additives that help lube the injection pump.....but that's another topic! if it's mileage you after the tdi's can get about 50mpg if you right foots not too heavy....again, another topic.

[curtis rosche]

if you right foots not too heavy....again, another topic.

no where near a light foot,,,,, i may have hit 100 at one point when a older man in a mustang with his wife decied that he should try to cut me off and then try to pass me,,,,,,,,

[Greg Portland]

Absolutely do NOT blow out your air filters. Compressed air crushes the fibers, seriously restricting airflow going forward. Used to crack me up at the old shop when someone would buy an expensive K&N filter, then "maintain it" by blowing it off with compressed air. In a matter of moments, their fancy free-flow filter worked worse than a crappy NAPA filter. Use a quality OEM filter, and maybe knock the dirt out by slapping it on the ground. But don't mess up the filter media (K&N or regular old paper filters) with compressed air.

The service manual on my Honda mower specifically recommends blowing out the (paper) filter but at low psi (10-20psi IIRC).

[Dave Lehnert]

Just a note about octane ratings.

May not be the same at all stations but the place I worked ran a gas station. We only had two tanks. Low-end and high-end octane. The middle grade was just a blend of the two.