You can buy a bottle of fuel injector cleaner at any automotive or hardware and pour it into your gas tank for an extra 3-5 miles per gallon.
No
Diesel.
yes and more horsepower
No it will not give you better performance or increase gas mileage. Gas mileage and performance will decrease only if you use it. leaving it off is like not having it at all.
No it does not give you better gas mileage, all it does is helps with any loss of horse power and white smoke coming from the tailpipe due to burning antifreeze.
Yes, higher octane gas does give higher gas mileage for your car. However, the increase in gas mileage may not as great as the increase in the price of the higher octane gas.
New spark plugs with the proper gap will give your car the best possible gas milage.
No it does not. But it does give you somewhat better gas mileage.
Yes it can, depending on your driving habits.
Bicycles give you more gas mileage.
It could, if the old gasket had failed.
for any car to get better gas mileage get a better flowing intake and/or exhaust or get it tuned