gbratk

Hello,



I have Cayenne S 2004 and I can get better then 11MPG. They said that is nothing wrong with the car, but I know that this is not normal. I drive it really carefully and on hwy i don't go over 85mph, and I can get better MPG.

I think it's worse in hwy then town driving, which is really strange. But the PCM show me average 16mpg, which is way way off.

Can someone help me with this problem

Thank you

Slow Guy

When was the last time the air filters and plugs were changed?

gbratk

Few month ago, I changed air filters, coils and plugs. there is also no error codes.

I don't know maybe it's normal, but when I turn off engine white smoke is coming out of exhaust for few minutes. Probably condensation, but why so long with engine off?

hahnmgh63

I would be extra cautious and have a leakdown check done on the engine & cooling system but other than that I agree with Bill, plugs & filters (OEM preferred). The pig does start using more gas once you push it past 70mph due to aerodynamics/drag. How long are your trips? Shorter, longer? Short trips and you may still be getting condensation evaporating/burning after shutdown but you shouldn't see it on a longer trip.

gbratk

There is no leaks, thats for shore. Coils and filters are oem, but the plugs are Beru.

I'm doing lots of long trips, and there come the days when I use it on short distance, but mpg is always the same. I'll check for condensation when I come from long trip.

steve_Cayenne

Probably obvious ... but are your tires properly inflated?

Are they the standard size for the rim (discrepancy between 11 and 16) ?

I have also had previous vehicles with slightly seized brakes. Is one wheel hotter to touch than the others after a trip?

gbratk

I'm checking tire pressure often, last time a week ago, when I changed summer for winter tire.

I have summer 21'' (pirelli 295-35-21) and winter 19'' (pirelli 275-45-19), booth wheels are OEM.
But MPG is the same with summer or winter tires.

Brakes, I also checked this, coz I also change discs and pads, few month ago.

I was thinking. Could it be O2 sensors? Will in that case have a error code? Or it's maybe bad and it's not working 100% right, but it's working in some way and don't throw an error code?

wwilliams88

Could it be a bad or dirty mass air flow sensor (MAF)? I cleaned mine in my Toyota after the gas mileage dropped and it helped.

gbratk

I cleaned booth MAF today, I'll see if there is any difference, but I doubt, coz they were look like new.

chasz

Long shot but worth the question: What brand and grade of fuel are you using?

gbratk

I use OMV 95 octane fuel.

chasz

Last idea for me. At what elevation are you primarily driving?

gbratk

around 200 meters.