Car is running fine right now but I've noticed my fuel mileage is down a bit (used to get about 250 miles to the tank, now about 230). Would putting Seafoam in to the fuel tank on the next fill up be a worthwhile risk ($ risk, not engine risk) or should I look elsewhere for my lost MPGs? I've never put anything in to the fuel before and have had the car for about 10,000 miles (sitting at 36,000 total), but I only run Shell VPower on my car and have read that it essentially does the same thing as Seafoam would. Not sure if this is correct but any info would be great.

 

I get 320 in my tank. Maybe your local gas station is cheating you at the pump? Try a different Shell gas station.

 

Shell is a top-tier detergent gasoline -- I personally would look elsewhere for the lost mileage (air filter, tire inflation, extra weight in the car, driving habits, weather, a/c usage, etc.) first.

EDIT - you're in Canada. Little known fact, all Canadian gasoline contains no less than 5% and no more than 10% ethanol due to a federal regulation change. I would attribute your mileage drop to that (I myself lost a few MPG and was wondering what had changed as my route and habits and maintenance routine had not, until I read about the change). Even V-Power, which used to be ethanol-free in Canada and the US, has to contain at least 5% ethanol per the feds.

 

Do you have any mods/tuning done to your car? Is it mostly highway driving?

Majin, I fill up typically in the US (I'm about 10 minutes away from the border) so I'm wondering if it's maybe the specific Shell I'm using.

 

Try cheveron gas supossed to be ethanol free... or maybe thats just their 94 octane

 

The light comes on when you have about 1/4 tank left. That's usually the reserve amount.
14.5 gallon tank and light kicks on for me at 10.5 used. (73% used).
The most I've filled up was 12.8 gallons. The fuel level looks so low so I'm too scared to run it more. Plus, its bad for the car.

How are you calculating your mileage?
Fill the tank up and reset the mileage.
Drive and fill up again.
Calculate MPG by dividing mileage by the gallons filled up?

This doesn't factor the variance of the actual tank being completely filled up though...

 

Good plan. I know the light typically comes on when you have less than 50km of driving fuel left in the tank, but if what was said earlier is true, about 17 liters of gas remain when the light comes on, which should translate in to over 100 km left on the tank. Whenever I fill up I usually put about 13 gallons of gas in to the tank. I just don't want to risk getting stranded but I will give this a shot.

 

The amount of fuel that you actually have when the warning come on is dynamic. If you're caning the car through the mountains, the actual amount of fuel left in the tank will be greater than if you're tooling along the freeway at 70mph.

 

for the OP to compare

mainly spirted city driving/traffic

i will get about 300 +/- a lil bit when my low fuel comes on... i'll drive it for a short bit and toss in on average 40-45 liters of gas

always using cheveron 91 or 94

 

Consider using 1/3 can of seafoam[tm] sucked into a vacuum line to clean carbon deposits on the inside. We run rich at WOT - so we build up a lot carbon (just look at the soot on the tailpipe

So 1/3 in the gas tank in your case may not do much (but won't hurt either) to clean injectors.

Google detailed directions to seafoam the intake/engine. If you don't find it - then let me know and i will post it.

 

Does this guy explain it well? How easy is it to pop off and replace the hose he pulls? He mentions that you need to find a vacuum line that has suction. Would that hose not always have suction?

 

^yep.
I used the BOV vacuum line (very easy to get to...), others use the brake master cylinder vacuum line.