I have to get a new vacuum switching valve for my 1987 toyota pickup. I was just wondering what it does, and if a broken one would cause my truck to not idle. It still runs fine when i drive it, but when i push the clutch in the RPM's get really low until it dies.
This valve probably is the EGR control valve - the computer monitors the EGR flow and controls the EGR valve opening by switching vacuum to it for opening or bleeding vacuum off for closing. If this valve fails to completely close the EGR valve at idle, the problem will mirror your symptoms
