Need help!?!

There is a gauge light in the lower right bezel of the "optional" instrument gauge cluster that shows a gas pump with three drops next to it. There is no mention of it in the owner's manual and I've had no luck in other forums finding out what it is. Anyway, while driving recently (flat surface, 55mph), this light came on very slowly, stayed on for a second, and then faded out again; did this once more about a minute later. Since then it hasn't happened, but my check engine light came on for the first time about a week later, so I'm wondering what the heck is going on.

As for the check engine light, I've replaced all the fuel with Chevron Supreme 93 octane, added 20oz of Techron, replaced the gas cap, and reset the light manually. So far so good, as it hasn't come back on.

But what about that weird light? I've seen similar ones in diesel vehicles indicating poor/wet diesel fuel. However, there are no diesel Rangers out there, I don't think this instrument cluster is shared on any other vehicles that are diesel, and I'm sure Ford wouldn't put a light bulb in it if it wasn't required.

Any ideas?

Thanks.