Those ratios sound about normal for a tracker / sidekick. I cruise at 3500 on the highway all the time. Won't hurt it a bit. ( I've got over 254,000 on my '93) still runs like new.
You didn't mention what vehicle you have but again if its a tracker / sidekick that switch under the dash resets the 'check engine' light. Its programmed to come on at certain mileage intervals (every 50,000 I think).