Ok so I have an 89 GTU N/A and I have an idle problem. It fluctuated between 1300-1600 RPM's but get this. If I put my foot on the brake and let the clutch out till my engine speed drops below 1000 it will stay there after i put the clutch back in. What would cause that?

 

i had the same problem and it was a vacume leak

 

ok cool. now all i got to do is figure out where it is coming from lol well guess it is starting fluid in the engin bay now lol