88 merc grand marque, 5.0 L, FI, Air, 160K.
Problem: rough idle, stalling, choppy during normal driving, hard to start.
EGR valve has been replaced, same problem. However, when the vacuum line to the EGR valve is disconnected the problem goes away. I am not really sure what the EGR valve does or how it works. Could there be some kind of blockage in the air plenum that it attaches to. Any ideas on where to go from here would be appreciated. It has new plugs, wires, rotor, coil, and fuel filter. Thanks in advance for any help.
The problem might be a 25.00 dollar part called the egr solinoid. It's small and has two wires and two small vacuum lines lpugged in to it. When you pull the vac hose off the egr is there vacuum at idle? There should not be!
March, 24, 2007 AT 2:51 PM
Thank you for your reply.
Yes, there is vacuum to the EGR valve at idle, according to vac guage there is about 2 lbs.
Is the solenoid controlling the vac at the EGR valve? I take it if this is working properly there should not be any vacuum at the EGR valve at idle.
Thanks again for your help with my problem.
March, 24, 2007 AT 9:02 PM
Replace the egr solinoid. Done! Get the codes cleared afterwards or the light will stay on for a while!