Horrible Gas milage

[Boxster02]

I own an 02 Boxster 2.7(tiptronic) with 68K on the odometer. Recently the gas milage has gone to crap, maybe 15 mpg city/hwy. Recently I have noticed a change in the exhaust note and it just doesnt seem to have the same zippy feel. Sometimes when starting cold it make a lazy cranking sound (sorry, not sure how to explain it ) before firing up. I know it has a leak at the RMS, but I dont think it would cause these symtoms. Any thought? :(

[White987S]

Maybe this is an issue with your MAF. Also, do you ever run a high-quality fuel injector cleaner? One with Techron? Maybe you sound run a few tanks of fuel with a good high-quailty fuel cleaner.

[WARDHOG]

Change your plugs and if you do use a fuel injector cleaner in the gas tank, change your oil after a tankful of treated gas. Also, clean out you air filter. :welcome:

[Boxster02]

Car has had all its maintenace at 60K and a recent oil change. I also cleaned the K&N air filter for good measure. I have treated the car with Techron concentrate. Seems to run better if I use an octane boost. Although it did throw out a HUGE cloud of white smoke the other day (usually just little puffs ), but still no check engine light. If it was the MAF, wouldn't I have some idle problems since the fuel/air mixture would be wrong? Thanks for the feed back!!

[tommy914]

Car has had all its maintenace at 60K and a recent oil change. I also cleaned the K&N air filter for good measure. I have treated the car with Techron concentrate. Seems to run better if I use an octane boost. Although it did throw out a HUGE cloud of white smoke the other day (usually just little puffs ), but still no check engine light. If it was the MAF, wouldn't I have some idle problems since the fuel/air mixture would be wrong? Thanks for the feed back!!

How long ago did you add the K&N filter. Those can cause problems with the MAF and other compenents because of the oil in the filter.

[Boxster02]

Added the K&N @ 60K. Car ran like a million bucks after the service. Im just trying to do some homework before taking it to the dealer. Dealer in my area is under investigation for shady business practices. :(

[djantlive]

who did the 60k service? make sure the plugs were done. i would not use kn filter as it often causes maf going bad. clean your maf sensor with electrical cleaner spray. make sure your tires are properly inflated.

exactly when did the milage change occur? before 60k service? what other changes were done before this issue?

[Boxster02]

60K serice was done my me. Changed plugs, oil, oil filter, air filter, new tires, cleared debris from the radiators. I assumed my car has no fuel filter as I could not find one anywhere, does it? Tire pressure checked once a week, always good. Peter Smith of PCA says the K&N and BMC filter's are not at fault for a faulty MAF, but rather faulty electronics within the MAF. If MAF was faulty wouldnt my CEL come on?

[Donie]

I assumed my car has no fuel filter as I could not find one anywhere, does it?

I do believe there is one in what would normally be referred to as the transmission tunnel underneath.

[reefish]

I assumed my car has no fuel filter as I could not find one anywhere, does it?

I do believe there is one in what would normally be referred to as the transmission tunnel underneath.

Change out your fuel filter and you will see a big difference. Fuel filter is directly under the driver seat but you will need to take out the plastic cover -under belly....also use disconnect your negative terminals on your battery before replacing the filter....

[Boxster02]

I read that my 02 has no fuel filter that is changable. I can not find one for sale on any website, only for an 01 and older.. I thought the Boxster got a returnless fuel system in 02, not 03.

[Loren]

I read that my 02 has no fuel filter that is changable. I can not find one for sale on any website, only for an 01 and older.. I thought the Boxster got a returnless fuel system in 02, not 03.

You are correct - no fuel filter from MY02 on.

IMHO you need to have the fault codes read and report them here - otherwise it's just shooting in the dark.

[aviator at elstree]

Hi

I have exactly the same problem

I get no more then 20 mpg driving carefully

This has been going on over 5 months

I had rough running, changed the MAF sensor which cured the rough running, then someone sugested it may be faulty so I changed it again

Then it failed an emmisions test so I changed the Lambda Sensors. It passed.

I have had it read by a Porsche agent and there are no codes

I am at a loss as to what to do next

Dave