I am having the same problem with my 93, except mine is an automatic. However sometimes mine decides to idle normal again on its own. I found that spraying the Mass air flow sensor with some cleaner, and d/c and re connecting all connections on it makes the problem stop for a period of time. Then again its quite possible that its a fluke that doing this is helping at all. My next step unless im told otherwise is to do a full tune up and possible change that Mass air flow sensor..