P0401 - Already changed EGR valve and solenoid, what's next?
Hey all, my 1st post here. Like the title says I'm getting the P0401 code (insufficient flow) on my 2002 Galant LS 4 banger. Prior to changing the EGR valve and the solenoid, I noticed the vacuum hose from the valve to the solenoid was disconnected. When I reconnected it, the car started to sputter and die when below 1K RPM. I then ordered a new valve and solenoid and replaced both, including the gasket. I also cleaned the carbon buildup on the intake manifold ports. Cleared the code and the SES light stayed off for about 15 miles then it came back on. I'd like to know what else I can check to get rid of this code once and for all. The car has 102K miles and the timing belt and valve cover gaskets were done 10K miles ago, it's in great condition otherwise and drives great. Any help is much appreciated.