You loose some you win some

[bvhout]

Hi,

It is now for about 5 months that I own a 2003 Boxster S during which I've done 7,000 miles on top of the 80,000 it had already done. Over the last two months -probably after its last service - I got the impression that the car was using more fuel than when I just got it. About 25 miles to the gallon, with about 80% of all miles are highway miles. Last week after buying gas, I suddenly observed that I was using about 33 miles to the gallon, a figure that I'd never seen before. I also heard some strange noises and within a minute something appeared to have fallen of my car. I didn't know what, but the car seemed to drive fine and fuel use was brilliant, above 30 mpg, never seen before. When home I couldn't find anything that could have fallen of.

The next day confirmed the fanatastic figures on a 120 mile trip. Then it occurred to me that I might have lost my fuel cap, and indeed, that was what it was. I simply had forgotten to screw it back on and as such found out that doing so improved my fuel use dramatically. The new fuel cap has arrived without a noticebale change in fuel use.

I had assumed that the increase in fuel use was related to the age of the engine and I was already scared that thus was gonna be costly. It isn't 15 pounds for a new fuel cap and many many savings in fuel. I've never been so happy after loosing something.

Ben

[sasha055]

Interesting, I wonder why would a fuel cap affect mileage..

I should probably take off my fuel cap, I rarely get more then 18-19 mpg, that's 50/50 driving

Sasha

[Loren]

Interesting, I wonder why would a fuel cap affect mileage..

I should probably take off my fuel cap, I rarely get more then 18-19 mpg, that's 50/50 driving

Sasha

Running without a fuel WILL give you a CEL and fault code. US EPA law requires a sealed system.

[RFM]

European also give an error code + CEL and a rough running engine, unless something on the system is wrong.

[bvhout]

Hi,

I hate to tell that I don't know what a CEL is.

I'm talking about the sort of plastic fuel cap that you turn on and off. I didn't get any faulty messages and the engine ran smoothly with and without. Just used a lot more gas with the old fuel cap.

Ben

[ABQautoxer]

CEL = Check Engine Light. Also called an MIL = Malfunction Indicator Light

Not having a properly sealing gas cap will trigger that.

[sliderr]

I hate to tell that I don't know what a CEL is.

Man I wished i could say the same !