Fuel economy took a major hit

[Saggy]

I've got a 95 Nissan Sentra that was getting 30 MPG. I don't know when I noticed it, but I've noticed lately that I'm only getting about 20-22. In more practical terms; I was getting about 400 miles a tank, now I'm getting 250-300.

 

What's the simplest, cheapest thing that I could try to improve this?

 

 

I'm fairly sure that I need an oil change. I've put about three thousand miles on it in three months. A thousand miles a month probably isn't good.

[BCspeed34]

Change the spark plugs, change the air filter, and run premium fuel. That should do the trick.

[lurchseesu420]

What type of gas are you using? Remember, the higher the ethanol content, the sh*ttier the gas mileage will be. And sadly, 100% gas is getting harder and harder find.

Edited November 13, 2008 by lurchseesu420

[Picolini]

What type of gas are you using? Remember, the higher the ethanol content, the sh*ttier the gas mileage will be. And sadly, 100% gas is getting harder and harder find.

That was going to be my first guess.

If there was a sudden drop in fuel economy it could be that your area or the station you go to the most switched to a 10/90 ethanol/gas mix. This can drop the fuel mileage quite a bit. Maybe not as bad as yours though.

But like Lurch said, the mix is spreading.

 

Has the car been running the same? Any noticeable differences in the way it sounds or runs? A nice tune up like BC said could help, and an oil change definitely wouldn't hurt, and could add to poorer gas mileage.

[silvermanblue]

Is your check engine light on? I don't know but it may be an oxygen sensor getting buggy.

[fuckindumass]

 

Is your check engine light on? I don't know but it may be an oxygen sensor getting buggy.

Right on.

 

If I was hell bent, I'd do a compression check. If I got a low cyl, I'd squirt some oil in and recheck. Still low, I'd guess valve or gasket. Look for bubbles coming up in radiator while engine is running for gasket problem. Of course you've already inspected the spark plugs. A water mist over the plug wires while idling should expose any issues there. You should be able to see light through the air filter if it's not clogged. An 1/8" hole drilled in front of the cat will reveal restriction, hollow it out and fix the misfire before replacing it if it's melted down. A sheetmetal screw closes the hole. A new timing chain has a few crank degrees of slop. Once it gets past a dozen performance drops off. Pop the cap and rotate the crank to take up the slack, mark the dampener or pulley, reverse rotation and stop as soon as the rotor moves. Measure how far the crank turned, do the math. Of course you've already inspected the cap and rotor. Don't forget carbon tracking inside or out on the cap. Hook up a vacuum gauge, should be +20" at idle, rock solid steady. Rapid fluctuations usually means valve/guide issues, wandering points at fuel mixture. Low means a lotta things. Check all your vacuum lines, wiring. Check your battery, if you're constantly pushing 25 amps into a bunch of dead cells you're burning more fun juice to do it. Fuel injectors wear out, especially if they're squirting alky. They can get outside the box, if ya know what I mean. Check your throttle body for carbon buildup at the butterfly. Keep that sh*t clean. Make sure all connections for air induction are secure. Mass air flow sensor can't work if you got leaks. I'll bet you'd notice the odor if you had a fuel leak, but can't hurt to inspect. Dragging brakes or flat tires would be obvious. Make an appointment for a psychiatric evaluation. If you're in a manic phase of bipolar spectrum, maybe you're just hittin the go pedal harder?

 

Sorry no sentence structure, paragraphs etc. Beer drinking and gear wrenching need no grammar.

[tuff_luv_capo]

Lose weight. My friend has the exact same sentra, and gets horrible gas mileage with multiple people (aka you) in it.

[92F]

Changing fuel want make an immediate increase on your mileage consumption. I would change air filter and fuel filter.

[Mega]

plugs air filter oil compression check.

[Picolini]

Lose weight. My friend has the exact same sentra, and gets horrible gas mileage with multiple people (aka you) in it.

Little harsh there buddy.

Besides, it just got bad. So unless he gained another 100+ pounds suddenly I doubt it'd be the reason.

[swolo yaggins]

Lose weight. My friend has the exact same sentra, and gets horrible gas mileage with multiple people (aka you) in it.

hahaha