Toyota Repair: 2000 Corolla - vibrations after startup, toyota corolla, toyota cars

Question
Hi Ted,

My 2000 Toyota Corolla (w/ 60k miles) vibrates noticably after startup.  After the engine warms up, however, the vibrations disappear.  The vibrations are strong enough that I don't think this is a result of standard wear and tear.

I've noticed that my gas mileage is down pretty significantly as well, it's at about 25-28 mi/gal.  When the car was new, I measured 37 mi/gal under the same driving conditions.

Could this be a problem with "oil sludging?"  I read that Toyota cars from 1997-2002 have a problem with oil gelling/sludging in the engine.  If this is the cause, it would seem to explain why the vibrations go away when the engine is warm, since the oil liquifies?  I followed the oil change schedule as recommended, but apparently sludging can still occur regardless.

Have you encountered this vibration problem before?  My other theory is that the catalytic converter is clogged, but I hear that doesn't happen very often.  I'd appreciate any insights you have.

Thanks a bunch,
Sam Kang

Answer
The oil gelling issue only applies to certain Camry, Avalon and Sienna engines, Corolla engines are not involved.
Is there a check engine light on?
There is a service bulletin regarding a rattle noise from the engine especially when cold, it involves replacing the belt tensioner and the accessory drive belt, I recommend having a toyota dealer check it.