98 Sunfire Swallowing Gas by the Gallon!

[wolfetundra]

I have a 98 Pontiac Sunfire. Recent purchase. The tank was almost on E. I put in $10 at about $3.19 per gal. That put me just under half. After driving around for 30 miles (city), I now read just about 1/8 tank. If I turn off the car and rotate the key forward, the needle goes up slightly above half. Tapping on the cover raises the needle about 1/12 every tap until it reaches full. Am I really burning that much fuel or is it some error somewhere?

SE Coupe 4 cyl, 2.2 Liter.

 

[melsg5]

Your not going to get an accurate MPG reading by looking at the position of the gauge. Fill the car up completely and write down the mileage on the odometer. Drive the car till its 1/2 full or even less. Fill it up completely write down the number of gallons you put in and the odometer mileage. Subtract the first mileage from the second mileage to see how many miles you have gone and then divide that number by the number of gallons you put in the second complete fill up. That is your MPG. Make sure you have a clean engine air filter and that your tires are properly inflated to the recommended cold pressure.

 

[wolfetundra]

I got the car from the dealer and they detail everything. Makes it hard to tell when something is wrong. The downside I hate when buying from dealers. It has new filters and fresh fluids. I haven't checked, but the tires "look" properly inflated. That is, only tread is touching the ground. When I air a tire at gas stations, most guages are not accurate, so I use that as a guide to indicate the tire is roughly filled correctly.

I need to drive some 200+ miles to get home (visiting family). So I will be able to do that on the way home. I'm driving up the I-5 corridor in CA so there's plenty of gas stations. I will give that a try.

I'm wondering how, if I have a 15 gallon tank (according to Pontiac, and the owners manual), how $10 can fill me up half tank.

 

[if6was9]

If it's anything like my '01 Blazer, the fuel gauge becomes unreliable under a 1/4 tank. Sometimes it will spike up to half a tank, then drop back. Sometimes it sticks at 1/4, and then will show the low fuel light. I've learned to watch my trip-ometer closer when nearing a 1/4 tank.

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[melsg5]

Buy a digital tire gauge, you cannot accurately eyeball tire pressure.