I have a lexus ls 400,152,000 miles. The problem start with the car runnig hot. So the car overheated. Now the car is idoling rough.I have no power taking off, it is stugggish. But it runs once it get started. The valves rattle but not bad.I also smell gas, and it is burning a lot of gas. There is no smoke coming from the car. It did not overheat long but now that it did it is running bad. It is a 1990 lexus ls400 152,000miles. Before overheating it ran excellent. Pease help. What could be the problem. Also it keeps running hot.