hello i just recently purchased a 1988 fourrunner but i have one problem with it and that is when i start it the idol goes from about 3000rpms to 1000 rmps and it just goes back and forth between those for about 3 or 4 minutes untill it warms up.... i was just wondering if anyone on here might know the problem and any help would be greatly appreciated.

check the coolant level. have a toyota dealer chk if the head gasket recall was done.