1990 b2600i high idle-- help!!
 

I am new to this so please help if you can. Started about a month ago. Most of the time it will idle ok at start up but as it is driven and warms up the idle will go to 1500rpm. Then it will climb to 1750rpm and bounce up and down to 1500rpm. If I shut it down for say 20 minutes and start it up it idles normal until I drive it for a couple of minutes and then bounce up and down again. Checked for vaccuum leaks and removed the vaccuum line from the fuel pressure regulator to check for fuel. Cleaned mass airflow sensor with carb cleaner and checked for wiring problems. Runs great at 65mph but when I stop at a light the idle is high and fluctuating.