I have been having trouble with my engine idling really low at start up about 500 and then it will go up to about 700 and then back down to 500 and it will do this for a while and will sometimes stall and die on me. But when I drive the car and it warms up it idles alot better. Then it starts miss firing really bad when i give it some gas and it is barely drivable and i have to limp home and if i let off the gas too quick it dies. I was planning on checking for vaccum leaks. What is the correct procedure for finding vaccum leaks or measuring the vaccum level?

 

Some people use tb cleaner spray, or something similar. Some have used propane. You can monitor the MAP reading with a scanner or just use a conventional vacuum test gauge. A stock engine should be around 20 inches of vacuum at idle.

Have you checked your EGR valve to see if it is sticking/stuck open?