I've always filled premium... and I've had some engine hesitation problems since I bought the car when at low rpms /1st & 2nd gear (tip), where the rpms dip below 500 and struggles for a second or two, even stalled a few times when coming to a stop. Last week I had to fill regular because premium wasn't available and since then it's been running smoothly, with no hesitation whatsoever. How could that be?! Is this a sign some faulty part needs replacement?

 

i had thought that filling cars like the 996 turbo and 997 turbo with anything less then 91 was dangerous?

 

Be careful where you are buying your gas from. I have heard stories of truck drivers being paid to drop regular into premium tanks. I like to get my gas from shell or sunoco.

 

Sunoco and BP are the best. Mobile is great for NA cars but not so good for FI cars

Sam - is your cars stock?
I noticed you are in Dubai - so I assume Sea Levels, relativly high humidity, and hot - correct?
Can be an issue with a tune. Please remember what regular burns better, ignites faster/easier but dangerous under boost - detonates

Would look at your spark plugs/coil packs

 

In Dubai where I live it's 95 RON for "special" and 98 for "super" (premium)

I wouldn't go as far as saying it's dangerous (it's not), and the car is designed to adjust based on fuel type but it's certainly designed for premium to get performance as per spec.

But i'm surprised no more RPM dipping < 500 when stopping and engine hesitation since i filled "special" instead of "super".

 

Yes 100% stock Turbo S. Spark plugs are fine - had them checked with the porsche diagnostic tool for any misfires.. they're all fine. MAF maybe?

 

When a truck delivers fuel to stations does it have 3 separate compartments? Or is there 93, and regular. And when you buy middle grade does it mix some 93 and some 87? I've seen stations with four to five different grades of fuel for sale. Is it different octane mixes or actually different shipments. I've also talked to some drivers of fuel trucks that say all the fuel they deliver is the same. He says the same trucks deliver the same gas to discount stations as well as sunoccos and shell.

 

A truck has 4 compartments totaling 9000 gallons. One for regular, plus, super, and diesel. Some stations mix regular and super to create plus. Others have all separate tanks for each grade.

The problem is that some shady station owners may get their fuel from unreliable sources OR they have different grade fuels poured into the premium tanks. In HIGH horsepower vehicles thats a big problem.

 

pumping your FI car with regular gas is fine as long as your not boosting, higher octane prevents dentonation, so generally you always want the highest grade gas possible

always pump from Brand Gas Stations like Shell, Mobil, BP etc.. that way you know your getting the actual Octane rating, pumping from the mom and pop station they will just use cheap gas as their premium.

 

Why would mobile not be as good?

 

Get the highest pump octane rating from Shell or Chevron as they have very good additive packages. It that's not enough you can find 100 octane unleaded at some stations. Half a tank of premium and 100 octane unleaded always seem to give the car a bit more kick.

 

Thanks for the advice about filling up at Shell, Sunoco and Chevron.. except I live across the world where the gas stations are operated by a few government owned entities. There are no mom and pop shops. We have only two grades: 95 RON and 98 RON.

So any explanation why my car would run smoother with 95 vs. 98? Faulty sensor not reading 98 correctly?

 

Small vacuum leak or faulty MAF? Did you scan for codes?

 

Yes but no codes showed up... hence couldn't fix the hesitation problem and been living with it.

 

[QUOTE=Sam996TTS;3351554]Yes but no codes showed up... hence couldn't fix the hesitation problem and been living with it.[/QUOTE

hesitaiton often are are a maf problem....i would clean it at first ore try a new one