Two problems related to cruise control have been reported for the 1999 Lexus RX300. The most recently reported issues are listed below.
3 episodes of severe acceleration terminated by shifting to neutral. In each case the rpm cycled from 3,000 to 8,000 and then spontaneously returned to normal after about a minute. In neutral gear. I was unable to overcome acceleration by braking. The gas petal fell to floor each time but was not stuck and returned to normal after the episode was over. These 3 events occurred in a single week. I felt there was some malfunction of the cruise control--which I never use. I had the cruise control disconnected at a local garage and never had another problem. When I told the Lexus dealer about this at the next routine service visit, they said they had never heard anything like this and did not suggest further action. I never reconnected the cruise control. I report this now because of the current concerns. This was clearly electronic in some fashion and I believe involved the cruise control mechanism.
Vehicles exhibiting poor acceleration while driving dealer replaced air flow meter and claimed tires were too agressive. Problem still exist.