Hello again, my last problem involved the IAC motor on my Regina-equipped 1990 740. Cleaning it helped, but the idle still drops and almost stalls once in a while... it's done it like twice since maybe. Cleaning still made a big difference, though. Perhaps the IAC motor is on its last leg. Or could there be another problem?

Anyway, my car still makes a subtle chugging/ticking sound. The frequency of it increases with engine speed, but it does not get louder. It's most noticeable when I'm cruising along. I have been unable to pinpoint it with the stethoscope. I also can smell what I assume to be exhaust gas coming from the motor. Exhaust manifold gasket and downpipe gaskets both seem fine; I cannot hear or feel any escaping gas. What are other possible culprits? Could it be the intake gasket, or maybe an injector O-ring leak, or bad spark plug threads? Could the head gasket be leaking?

Or am I just crazy, and its just a normal sound the injectors make as they open and close? My other Volvo is K-jet; I'm new to EFI systems.


On a side note, I'm going to be pulling the intake to replace the coolant temp sensor, since it gave a faulty code. Where is the EGR valve located? I'd like to clean it while I'm at it.

Sorry this was a bit long. I welcome any suggestions!