gas octane and cold starts

[puck]

I'm just wondering if anyone else has noticed this or if this might be a sign of an impending problem. You might remember, I just bought a 97 J30 with 55k about 2 weeks ago.

I test drove it a three times and it always started right up from cold starts. I noticed the gas gauge at the dealer was close to empty. When I picked it up, they had put 1/2 a tank of gas in. I'm not sure what type of gas they put in it. Several cold starts on that tank did not start right away. Sometimes I had to give it 2-3 trys before it started. After that tank, I put in 91 octane premium fuel and the starting problem continued and, if anything, became worse....it never started the first time with a cold start. It always ran fine otherwise. I brought it in for a regular inspection at the dealer (which it was due for) and mentioned the problem in passing. They couldn't find a thing wrong with anything, which was great except it still didn't start right away. (Fortunately, I learned, the inspections are free, too). With my most recent tank of gas, I put in the premium, of course, but this time it happened to be 93 octane. Ever since, it has started perfectly. According to my owners manual 91 octane is the recommended fuel, but I think I'll be sticking to the 93 for now. Any thoughts?

[greenwar]

Puck,

Thanks for the post man. I will stick to 92 and above as well even though mine didnt have a starting problem.

[Defiant]

Octane shouldn't affect startup- old, stale gas from a can at the dealer's might. Octane's more a concern under engine load, or hot-running.

[puck]

Octane shouldn't affect startup- old, stale gas from a can at the dealer's might. Octane's more a concern under engine load, or hot-running.

Ya, that's what I thought about octane, which is why I'm a bit perplexed. The only reason the gas thing crossed my mind was because the problem immediately went away after my last tank. It very may we be a coincidence. Time will tell.

[Q45tech]

Gasoline has dozens of specifications and OCTANE is a very minor one.

Reid Vapor Point and Diveability Index and 10% vs 90% Vaporization temperature, Density, etc, etc.

Strange that people obsess about octane and skip the important stuff.

Most times Premium is better quality than regular.