Does anyone know what the intitials INFL REST. stand for in a chevy lumina 1990?

It stands for Inflatable Restraint, more commonly known as the air bag in the steering wheel.

Some car manufacturers have tried a marketing gimmick whereby they sell you a new car that doesn't need much maintenance... proof: why, it only needs a tuneup every 100,000 miles. and change oil every 7500 miles. Don't fall for it. In most cases the only change to the car to make it need so little maintenance was to use platinum-tipped spark plugs. Big deal. Then when you do get to 100,000 miles and the car suffers for it, it is WAY out of warranty and no responsibility of theirs. I recommend at 30,000 miles change the spark plugs, fuel filter, and PCV valve and clean the throttle body as a minimum. This is a good time to check and replace or adjust any belts, and check the air filter.

Try reading the owners manual or take it to a qualified technician for a evaluation..