98 Lesabre gas mileage

[mark38]

Hi.My car has 92k miles.Im getting some bad gas mileage.I put gas in it to about the 3/4 mark.Now its down near the 1/4 mark and I only put around 100 miles(city) on it.Does that seem excessive?A tire or 2 might be a little low.Im in Michigan so its been cold and snowy here and such but dang.I bought the car in sept of last year and only replace the dirty air filter.I checked one spark plug and they were iridium so i figure they have been changed already.Any thoughts welcome.Thanks

 

[akmac]

The car had iridium from the factory, so they may well be the original plugs. Replacing them now wouldn't be a bad idea if that's the case. I would also check the coil packs and wires.

Your should make note of how many actual gallons it has used. The gas gauge doesn't reflect the actual capacity of the tank, so there's no way to know what your actual mpg's are just from that

 

[dohalloran]

If you fill the tank (68 Litres), the gauge should read above full for at least 80 miles.

Something is definitely wrong.

I am quite impressedd with the mileage I get. Mostly highway though.

I watched the low fuel light flicker and then go on steady, before I squeezed 69.4 litres into that same 68 litre tank.

I'm expecting high 600km ranges once it warms up here in the north.


The OD is great. City driving you will struggle a little.

 

[katoranger]

That actually sounds about the same as my car, but the only way to really know is to fill it up and calculate your mileage.

Fill it. reset the trip meter. Drive. Fill it. divide the number of miles driven by the number of gallons used. In the city you should be around 20 mpg.

These cars are heavy and stop and go driving means getting all that weight moving over and over again.

I get about 22mpg in town.

 

[mark38]

Well according to my owners manual the replacement plugs are ac type 41-921.(platinum plugs) and I have ac delco ITR4A(iridium) plugs in there now so thats why im thinking they are not the original plugs.

 

[gman1023]

That sounds about right. The gauges on these cars are not exactly accurate, they go from 3/4 to 1/4 extremely fast but take about 75-80 miles to come off the F marker at all if you fill the tank. Your gas mileage is the miles you've driven divided by the number of gallons used, I calculate it every time I fill up. It's really only possible though if you fill the tank completely every time. You should not go by the gas gauge in any car to estimate fuel economy, but these Buick gauges are well documented on here to read this way.

 

[Hawk]

Pull the dip stick and see if the oil smells of gas, if so I would be checking the FPR (fuel Pressure Regulator).

Keep track of miles and how many gals (lts) you need to put in. Take the miles div by gal and you get your mpg. If it is that low then you have serious issues of either a bad FPR, Injector(s), or leaky fuel line / fuel rail

 

[dcraig1000]

could be numerous things. dont go throwing parts at it until youve found something definite. pull the plugs and look at them. run the car at night and open the hood to see if there is any spark jump from one of the plug wires. check and clean the grounds on the coil pack bracket. check your air filter. clean you maf sensor. check the fuel pressure.