It’s 2008 and the outlook is grim. There’s rampant inflation. Food prices are soaring. Offshoring is sending your jobs overseas. The whole sub-prime mortgage mess is threatening to leave you homeless. That last thing you need is to be spending $4+ a gallon on gas. Here are 10 lesser known things to watch for in your quest to maximize your vehicle's fuel economy.
The Right Tranny: Learn to drive stick.
There used to be a day when the only two types of trannies were manual or automatic. Today, there's also post-op and pre-op. We'll be referring to the former nomenclature.
It's a well known fact that manual gearboxes yield better gas mileage than auto slushboxes. The majority of manual gearboxes are more mechanically efficient, and are able to put more power down to the ground with less drivetrain frictional losses. Less friction = more efficiency = less gas to get the car moving.
If you're driving an older beater like me, sell it and buy something with a stick. You can probably pull this off and break even (i.e. not lose money) on the transaction.
Keep the RPMs low
When driving stick, skip second and fourth gear unless necessary or it would unsafe to do so. Start the car in first gear, and dump it into third once you start moving. Depending on your car, you can use 5th gear from 35mph on up. Using 5th gear on the street at 35mph will keep your engine right below 2000 RPM, which will in many cases result in better fuel mileage than say, 4000 RPM.
If you're driving an automatic, refrain from flooring the pedal, as that will cause the transmission to shift at really high RPMs (near redline). If you're easy on the pedal, the transmission will do its job and keep the engine RPMS low.
Learn how to coast
In modern fuel injected automobiles, it actually makes more sense to coast in a high gear than in neutral. When coasting with your foot off the gas, the car will actually shut off the fuel injectors as there is plenty of load to spin the crankshaft, whereas in neutral, the car will fire the injectors just enough to keep the engine idling.
Empty the trunk
If you've got junk in the trunk, empty that ish out. It's dead weight that you're hauling around everywhere you go. Weight decreases efficiency, which in turn increases fuel consumption.
Cleanliness is next to gas miserliness
Keep your car clean and waxed. It's a tad easier to move a smooth and slippery hunk of steel down the highway at 60mph than it is to move a rough dirty hunk of steel at the same speed. Not a huge difference, but every little bit counts.
Check your idle
Check your manufacturer's guidelines as to what the normal engine idle speed is for your car. Generally it's between 700-900 RPM. If your engine idles higher than this when you're stopped, you're burning extra gas. Have a mechanic adjust your idle or hit Google
and figure out how to do it yourself - it's not that hard.
Check and/or replace your O2 sensor
The O2 sensor is responsible for informing the engine computer about how rich or lean the air/fuel mixture is. Often times, as these sensors age, they can throw said mixture off and have a drastic effect on fuel economy. Most newer cars have two or more of these sensors. They're usually in pretty tight, so it's a good idea to take your car to the shop to have these checked.
Check engine grounding
There are a series of electrical circuits at work under the hood. Sometimes after extensive maintenance/repairs over the years, some mechanic that's worked on your car may have forgotten to reconnect the ground straps/wires. If you've had an engine replacement, it's also possible that the mechanics who installed the new (or used) engine may have improperly grounded the engine. Search eBay for an engine grounding/ground wire kit for your vehicle. Some people have reported great success (gains of 3-5mpg) after installing one of these. While this may not work as well for everyone, it's worth a try as these kits are pretty cheap.
Check your ignition components and engine timing
Make sure your spark plugs, spark plug wires (if equipped), distributor cap/rotor are in good condition, as these tend to wear over time. If your car is not able to completely ignite the air fuel mixture for one reason or another, you will lose efficiency (and gas mileage) as a result.
Also make sure your timing is correct. You should be able to find a sticker under your hood indicating what the base timing should be. Have a mechanic reset your timing within factory tolerances. If your timing is drastically off, it can have an adverse effect on fuel economy.
Check tire pressure
Ok, so I fibbed. This particular tip is one you've probably heard hundreds of times before. Still, underinflated tires is a common problem. People can lose up to 3-5mpg with severely underinflated tires. Find out what optimum tire pressures are from the local dealer and make sure you check once a month to ensure they stay at optimum pressures.
