What is the problem? The idle going up and down while warming up? If so, that's not unusual for 89's and 90's. They use a wax pellet in the throttle body that opens up more airflow as it warms up, but as it lets cold air past it, it cools down closing off again. It ends up causing the yo-yo like idle while it warms up. I have seen many threads about this, do a search and you will find PAGES of threads asking the same question, even probably one by me from way back. I remember seeing at least one thread about removing the pellet to get rid of the high idle altogether, which also cured the erratic warm up idle as well, but if you live somewhere that gets really cold in the winters, you probably wouldn't want to do that...
