Double warning lights

A week after passing smog with flying colors, the "check gauge" and "check engine" lights on my '95 Ranger (with over 193,000 miles) suddenly come on together, along with a burning smell that is stronger in the cab than under the hood itself.

Temp also goes up fast, but not into the danger zone. Coolant resivoir was bone dry, so I filled it up and it doesn't appear to be leaking when not running (haven't driven it since, so I can't say if it's escaping while on the road). Oil was down a quart, and I do have a leak, so I topped off that too. Still have the lights, though.

Anybody have an idea what I'm dealing with and, more to the point, how much it's going to cost to fix, even ballpark?

Thanks!

My experience with "check gauge" light means one of your gauges is reading a problem, ie low fuel, overheating, low oil pressure. Mine came on when I was low on fuel. 95 3.0 Go to AutoZone or Aamco Trans, they both will read codes for "check engine" light for free. It will tell you where problem is. Good Luck!!

Thanks!