hay mate had the same problem with the small port 4age, all the regular caps were different and the guy at burson litteraly just looked at the pictures in the bosche booklet and was like bet u its this one, he was right. very strange that the mr2 cap didn't work. I don't know how important it is for you to get toyota but you could always try that, matching it by eye with the old one at somewhere like burson, may not help you if its a jdm rwd though.