lancewi

I know the lean bank codes are a well known issue and there are many threads on these codes. My truck has 206k miles so I just did plugs and coils. I also changed all eight injectors. A while ago the dpfe broke (one of the hose connectors broke right off) so that is new, as well as a new egr solenoid and egr valve. I bought a new fuel injection vacuum line and a new pcv valve hose assembly so all of those hoses and elbows are new. The pcv valve came with the hose assembly so that is new. I changed the fuel filter last month so that is in good shape. I also changed the iac and cleaned the maf again. Air filter is clean and I do not have a K&N intake or anything. I sprayed carb cleaner all around the intake but the only noticeable jump in rpm came when I sprayed under the air intake toward the throttle body. I have not been able to reproduce that jump again.

At idle I can hear the egr valve open. I know this is not supposed to open at idle. When I disconnect the vacuum hose from the top of the valve the truck idles nice so the valve is closing and not stuck. When it is connected the truck idles rough and bucks when in gear.

I can't figure out why the egr is opening at idle. Someone suggested that the egr port on the throttle body may be plugged. I figured this weekend I would buy the gaskets and take it off and clean it really well. I am not sure if that makes sense as to why the egr is opening. I figure it would be good maintenance to clean it anyway. But why is it opening??

The only other thing I was thinking was the intake manifold gasket. Does the 5.4 have only the plastic intake or is there an aluminum under that as well and should I do both gaskets (upper and lower)?

I am open to any suggestions anyone has if they can think of anything else I could try. Thanks in advance!

Marc D

The intake manifold gaskets are usually the main source of the vacuum leak that throws these codes however when you manually close the EGR valve by removing the vacuum line and get favorable results, I suspect your EGR pressure sensor is bad. This regulates the vacuum, only opening at higher RPM's. If yours is silver pot metal it is definitely bad since the new ones are black. Good luck.

lancewi

The DPFE is new and black from O'Reillys. I took a glance at it this morning and noticed that the righthand hose was a little loose so I put two 1/2" hose clamps on it (one at the DPFE and the other at the pipe that comes off the manifold). It is still opening at idle.

Still on the list this weekend is to clean the throttle body and get the courage to pull the intake and replace the gaskets.

I will keep you posted. Thanks for the response.

lancewi

I changed to motorcraft dpfe and egr solenoid. I took off the throttle body and cleaned all the ports. Put everything back together and it idles smoothe. Feels like a new truck.