i,m considering buying a 1999 solaro.did the oil sludge problem stretch that far?

Just use synthetic. No sludging to worry about with that.

The following vehicles have been acknowledged by Toyota as potential problems:

2.2 L I4
Camry Produced 8/96 - 7/01
Celica Produced 8/96 - 4/99
Corolla Produced 1998
Solara Produced 6/98 - 5/01

3.0 L V6
Camry Produced 8/96 - 7/02
Avalon Produced 7/96 - 5/02
Highlander Produced 11/00 - 7/02
Lexus ES300 Produced 8/98 - 7/02
Lexus RX300 Produced 1/98 - 7/02
Sienna Produced 7/97 - 5/02
Solara Produced 6/98 - 5/02

(yes)