Q: increased engine over load message.

Hi there. The message is coming on for the catalytic converter overheating. A misfire or leaking injector will cause the catalytic converter to overheat as raw fuel enters the exhaust system. Check the engine for a misfire and see which cylinder(s) is/are misfiring. Check the spark plugs and see if any of them are coated with fuel. If they are, then either the spark plug is not firing or the fuel injector is leaking. When driving your vehicle really fast will make the engine run at a faster rate and have less air in the system causing the engine to burn less making the exhaust system cooler than normal. When this happens the computer will compensate the difference with adding fuel. If the fuel injector is leaking or spark plug is fouled out, then the ECM (computer) will see this as a normal condition and turn off the message.

I recommend seeking out a professional, such as one from Your Mechanic, to help you diagnose your engine before you drive a long distance to prevent any engine damage.