The last gas question

[nemelek]

I am not sure if the elevetion that one lives at has a bearing on the fuel octane that can be used. I once had a 89 or 90 Nissan Sentra in which the owners manual suggested a higher octane at lower elevations. I always ran the cheap gas in Colorado with no problem. When I drove to California the car started to ping. Filling with a higher octane solved the problem while at the coast.

[newyar]

Originally Posted by nemelek

I am not sure if the elevetion that one lives at has a bearing on the fuel octane that can be used. I once had a 89 or 90 Nissan Sentra in which the owners manual suggested a higher octane at lower elevations. I always ran the cheap gas in Colorado with no problem. When I drove to California the car started to ping. Filling with a higher octane solved the problem while at the coast.

Altitude does affect engines. The air to fuel ratio does change between the thinned out air at high altitudes versus the denser air near sea level. However there's also a difference in gas quality; cheap gas at a cheap station may be truly cheap in every way. My Mazda RX8 does not like the cheap off-brand gas; I only put Shell in it. In a pinch I can use Chevron but it runs best with Shell. Tried some of the cheap off-brand stuff and the car ran like crap. Soon as I could I filled back up with Shell and the car was back to itself again.

The Yaris is more forgiving but I still put Shell regular in it. The few pennies you save in cheap gas you more than pay for later with repairs and having fuel injectors clog up, emission systems clog up, and engine gunk build-up.