Q. What causes my 1984 Mitsubishi Starion Turbo to vibrate on acceleration? It overheats in three miles of city driving. It cools down at highway speeds, but when it idles it shows low oil pressure. Are all these symptoms related, and if so, what is the cause?
A. Excessive heat is the common cause. It could be pinpointed precisely if I knew what transmission type the car has. If your car has an automatic transmission, have the fluid checked and stall-tested for slippage and overheating. If the transmission is manual, the engine's cooling system could be causing the problem. Have the fan, water pump, belts, hoses and radiator checked by a professional. I hope that the low idle oil pressure has not damaged the engine.
Q. We live on a long, dusty road about 10 miles from the pavement. The air filter on our new Ford 150 pickup gets plugged and wastes gasoline almost every week. What would you advise? Replacement filters cost at least $5.
A. A weekly cleaning of the filter with a powerful shop vacuum will help solve your problem. To make sure the filter has been cleared of dust, put a light bulb on the inside of the element. If the light passes through the micron-sized holes, the filter is still usable.
Q. My 1989 Pontiac Sunbird roars from under the car when it upshifts. The noise leaves in high gear, but it returns on downshift when climbing hills. Is this normal? The dealer claims it is.
A. If your car has the four-cylinder engine, he might be right. Test drive a similar car on the dealer's lot to see if the same thing happens.
Q. Is there any reason why ethanol-enriched gasoline should not be used in carbureted engines?
A. It has been in use for 10 years and has not ruined any engines or carburetors to my knowledge.
Q. What causes the engine on my 1984 Dodge to idle rough when it is hot? It runs fine when it is cold.
A. Have the engine tested on an oscilloscope for coil secondary behavior and/or fuel starvation. Manually choking may overcome the problem. Retorque all intake manifold bolts.
Q. Why does the steering wheel on my 1990 Honda rattle and jerk?
A. The reader writes that the steering wheel on his 1990 Honda rattles so badly that it's impossible to talk and drive at the same time. The rattling stops when the wheel is turned. The dealer won't help. Take the car to another Honda dealer. Unless you have logged unusually high mileage, it still should be under warranty. It sounds as if you could have a CV joint problem. Perhaps a mast jacket bearing at the top is loose or missing. If the other dealer doesn't help, call the Honda distributor, (213) 783-2000.