Just bought my son his first car. 03 lx with 208000 mi. Overall car is ok. But seems to run out of breath in high rpms. Spark plugs look ok. They are all consistant in color - tan. Air filter is ok. Only a little dirty. Not dirty enough to cause restriction imo. Any common reasons the car would be sluggish up top? Clogged cat? Bad timing? Seems to run just fine in low rpm but if you floor it it just takes forever to reach 6k rpms and theres no power.