One problem related to gasoline engine has been reported for the 1998 Toyota RAV4. The most recently reported issues are listed below.
The engine idleing speed sometimes goes up to over 2000 rpm. I took the car into the Toyota dealer in concord, nh who said I needed a new computer costing $1300 but it would be weeks before it was availble. Next day the idling returned to normal. So I told Toyota that it was not necessary to get the computer. However, the problem reoccurs and seems to right itself. Having the revs so high can be very dangerous, especially in heavy traffic. Personally, I think the problem is in the fuel supply system but I'd have to spend the $1300 on the new computer first to prove this.