Decreasing fuel economy
Thread Starter
Joined: Mar 2008
Posts: 3
Decreasing fuel economy
Hi everyone!
I've got a 96 E320 with 230k miles on it that is getting worse and worse gas mileage. I was going through my logs last night, and about 18 months ago I was getting an average close to 23.5 MPG. On my last fill up, I barely edged out 20.5 MPG. I've noticed a very steady and gradual decline in my fuel economy over the last year or so.
About 8 months ago, I put in a K&N filter, thinking that would help my fuel economy. I check my tire pressure constantly, change out the oil and filter regularly, I'm not particularly heavy footed on the gas pedal, but really my driving pattern hasn't changed much. The check engine light comes on periodically, and when I had it checked they said it was the fuel mix to the #6 cylinder and they needed to take the computer out of the car to fix it. They said it could cost anywhere between $450 to $1500 depending on what needed to be replaced.
I don't feel comfortable with that big of a range for the repair. My questions are:
[ul][*]Could this just be that it's an old car and I just need to deal with decreasing fuel efficiency?[*]Should I just suck it up and deal with that wide range for the repair and get the computer fixed?[*]Is there some other solution that y'all think I should look into?[/ul]
I've got a 96 E320 with 230k miles on it that is getting worse and worse gas mileage. I was going through my logs last night, and about 18 months ago I was getting an average close to 23.5 MPG. On my last fill up, I barely edged out 20.5 MPG. I've noticed a very steady and gradual decline in my fuel economy over the last year or so.
About 8 months ago, I put in a K&N filter, thinking that would help my fuel economy. I check my tire pressure constantly, change out the oil and filter regularly, I'm not particularly heavy footed on the gas pedal, but really my driving pattern hasn't changed much. The check engine light comes on periodically, and when I had it checked they said it was the fuel mix to the #6 cylinder and they needed to take the computer out of the car to fix it. They said it could cost anywhere between $450 to $1500 depending on what needed to be replaced.
I don't feel comfortable with that big of a range for the repair. My questions are:
[ul][*]Could this just be that it's an old car and I just need to deal with decreasing fuel efficiency?[*]Should I just suck it up and deal with that wide range for the repair and get the computer fixed?[*]Is there some other solution that y'all think I should look into?[/ul]
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Joined: Dec 2004
Posts: 2,410
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RE: Decreasing fuel economy
Gas mileage will deteriorate with age but is the reduction reasonable. Not sure.
What sort of oil consumption are you getting? This will point to what condition the engine is in. 230k miles is moving on.
Do you still have the old air filter. I don't like non standard stuff and since gas mileage got worse from the point this was fitted I would have a go with the old filter once again. Maybe it offers greater resistance to the air and is impacting the MAF setting which in turn is making the car run rich.
Don't wish to offer any advice re the computer.
If the guy knows how much he is going to charge you for the computer job he must know what is wrong and what he is going to do about it. Move it from the car. Why? I'd ask a few question along these lines to see if you can get a clearer picture of what is going on.
Stuart
What sort of oil consumption are you getting? This will point to what condition the engine is in. 230k miles is moving on.
Do you still have the old air filter. I don't like non standard stuff and since gas mileage got worse from the point this was fitted I would have a go with the old filter once again. Maybe it offers greater resistance to the air and is impacting the MAF setting which in turn is making the car run rich.
Don't wish to offer any advice re the computer.
If the guy knows how much he is going to charge you for the computer job he must know what is wrong and what he is going to do about it. Move it from the car. Why? I'd ask a few question along these lines to see if you can get a clearer picture of what is going on.
Stuart
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