[Q] Octane rating and cold engine start?

[96_WhiteBird_Manual]

Hi,

I have a 96 Pontiac Firebird 3.8L V6.
It seems my car is sensitive to fuel brands.

I switched from 76 to Arco, and I started to use 89 octane instead of 87 since engine seems making pinging sound once in a while.

After I changed to 89 octane Arco, it's harder to start the engine and had rough idling at night. I had this when I used Shell 89. But seldom had one when I was using 76.

Other cars seem kind of insensitive to fuel brand, but my bird is picky! [img]smile.gif[/img]
(Maybe my bird loves alcohol since 76 pumps said "It may contain ethanol".)

Any similar experiences? I changed fuel filter like 4000 miles ago, spark plugs and wires 3000 miles ago, and my car has 75,000 miles.

I appreciate any comment or any advice!

[99Camaro99]

use Chevron with Techron...

Chevron...simply smarter [img]smile.gif[/img] :rolleyes:

seriously I either use that or Mobil and the car runs great for me. My only complain is at cold starts it may clang for a second (sticking valve taps)

[greenasgrass]

arco?! im suprised you car even runs at all! you should only use chevron, use red line fuel system treatment (turned off the check engine light on my wifes car), and only use 87 octane as the owners manual says. i had a bad experience with using 92 octane when the reccomended octane was 87.

[img]graemlins/dunce.gif[/img]

[96_WhiteBird_Manual]

<blockquote>quote:</font><hr> arco?! im suprised you car even runs at all! you should only use chevron <hr></blockquote>

Thanks for your suggestion.
Yeah, I first thought Arco is not as good as others since they are cheaper, but I had no problem except engine start when cold, and rough idle before it warms up.

I once tried Chevron 89 octane, and I had engine service light on. :( I had to use engine fuel system cleaner to turn it off. I am using redline complete fuel system cleaner once in a while. Maybe I will try couple of brands with 87 octane.

[Dominic]

I have noticed my best fuel economy and performance on the ethanol based fuel 76.

Mobil, Arco, they both suck and I don't recommend them in California. In other parts of the country Mobil is fine, but here its just not very good fuel.

Run some fuel injector cleaner through your system and keep away from arco.

[greencamaro]

what doe you guy think of Texaco?
And I use 89 octiane and went to the track And only ran 15.99 I usally run 15.4. could this be one of the resones i was so slow.

[96_WhiteBird_Manual]

I think I will go back to 76.

I tried Mobil on my way to LA, and they were ok.
But I don't have Mobil near my school and home.

I guess 76, Mobil, Exxon are all made by Philips66, so they might be almost same.

I didn't try Texaco after I had problem with Chevron since Texaco and Chevron are merged. (Not sure whether they are different still or not.)

Shell is all around, but I had the same problem as Arco.

I see a few Valero, but cannot get any info on the web about their fuel.

76.com says they stopped using MTBE in California, so I expect slightly more efficiency and performance. (Like 3%? [img]smile.gif[/img] )