Dear Doctor: I own a 2002 Honda Odyssey with 92,000 miles, which I purchased with 60,000 miles. My problem is when I come to a stop; the transmission doesn't seem to downshift into first gear. It takes a few seconds before the van will pull away properly. My mechanic says that Honda automatic transmissions have problems and he has replaced another Odyssey transmission twice for the same problem. What is your expert opinion on the Honda transmission? Howard

Dear Howard: Honda has had some transmission concerns with its automatic transmissions. Check for any transmission trouble codes in memory or pending codes. Throttle position sensors can act up as well as internal transmission problems. You should check with either a local transmission shop or the Honda dealer.

Dear Doctor: I own a 1976 Buick Electra 225 with 152,000 miles. I always use Castrol GTX oil. Is it too late to switch over to full synthetic engine oil? Pat

Dear Pat: You can switch over to full synthetic at any time. You can also switch back or top off with regular oil at any time.

Dear Doctor: I am the original owner of a 1997 Saturn SC1 and live in New England. On cool mornings when I turn the heater on, the windshield fogs up. I have to turn the a/c on to clear the cloud. What would be your advice? Richard

Dear Richard: The fog is from emitting moisture, usually caused by moisture in the heater box. Make sure the heater box drain is clear and not clogged. The reason that the fog disappears with the a/c on is that a/c acts as a dehumidifier. You can also go to the local marine supply or home improvement store and purchase a small can of moisture absorber.

Dear Doctor: I own a 1997 Buick LeSabre that had a coolant leak. The shop replaced the intake manifold gasket, water pump and valve cover gaskets. The next day the "check engine" light came on. I took the car back to the shop and they kept the car for one week, but still could not find the reason why the light came on. Can you help? Bernie

Dear Bernie: Head to the dealer or a shop that has a qualified technician. The technician will check the trouble fault code and then will check the circuit that the sensor is involved with. One week to find the problem is unacceptable.

Dear Doctor: I own a 2003 Oldsmobile with an intermittent problem. The engine will start, but the dash gauges will not work. It takes about 10 minutes before everything works. I have been to two different shops but the problem still exists. Jean

Dear Jean: Intermittent electrical problems can sometimes take a long time to diagnose. At my shop we work closely with Identifix for these problems. I looked on the Identifix Web site and found the problems range from faulty ignition switches to body control modules. In a lot of cases the computer will hold a trouble fault code and not set the check engine light.

Dear Doctor: How effective is synthetic oil over conventional oil? Is it really worth the extra money? Stan

Dear Stan: In hot or cold weather synthetic oil does not thicken up. In my opinion full synthetic is worth the extra money if you plan on long-term ownership of the vehicle. Full synthetic also increases fuel economy mileage up to 1 mile per gallon.

Dear Doctor: I recently had to replace the engine in my 1990 Ford pickup 5.0-liter V-8 with a 1996 model year 5.0-liter engine. The current problem is a bucking sensation when the transmission shifts into third gear. It's really noticeable when I tow my trailer going up an incline. If I floor the gas pedal the transmission downshifts and the engine seems fine. What could be wrong with the transmission? Dave

Dear Dave: The first step is to conduct a full engine performance test, including both an engine-off and engine-running test. I think it could be either a lean condition or engine misfire. A lean condition can be caused by a lack of fuel or fuel pressure, or early EGR operation. Did you swap all necessary components from the old engine to the replacement engine? You can disconnect the vacuum hose off the EGR valve for testing purposes only and road test the truck. If the problem solves, then make sure to also check the EGR height sensor and solenoid.

Junior Damato is an ASE-certified Master Technician.

Send questions to: Auto Doctor, 3 Court Circle, Lakeville, MA 02347