Poor fuel economy

What is your question?

136,000 miles changed spark plugs and coils, runs smooth plenty of power. This lexus get poor gas mileage 14-17 miles per gallon, manufactur list much higher fuel economy Is it possible timing is off by one tooth. I'm not aware if previous owner changed timing belt. Any suggestions?

What makes this problem better or worse?

Na

How long has your 1999 Lexus ES300 had this problem?

Since I bought it at 125,000 miles