0401 & 0402 EGR Codes

[avocadoman1]

over the past several months i've received both of these codes on an intermittent basis.
0401: EGR flow insufficient
0402: EGR flow excessive
i've seen all the write-ups on the V8SHO website, but cannot decide the easiest fix.
is this just a simple replacement of the EGR or is there a flow restriction as well?

 

[Sagabu]

Try just cleaning it out first.

 

[avocadoman1]

i've done this test...

"With the engine warmed up and idling, apply vacuum directly to the ERG valve (your mouth and a piece of hose is sufficient). If the engine stumbles the valve is good. More than likely the problem is the DPFE(GR) sensor
and not the valve. If the engine does not stumble then I would take it off and see if the port going in to the intake is clogged.
The EGR valve itself very seldom fails."

my engine stumbles when i perform the above test...

however, if the DPFE (GR) sensor is bad/clogged, shouldn't i get a 1400 or 1401 error code?

BTW, where is the DPFE (GR) sensor located?

 

[SHOZ123]

Also check the two fat short silicone hoses that attach the DPFE sensor to the EGR tub. The DPFE sensor is mounted on the back surge tank somewhere just above the EGR tube that goes from the exhaust manifold to the EGR valve.

 

[avocadoman1]

can i access the hoses w/out removing the surge tank?

 

[SHOZ123]

Yes. May be helpful to remove the passanger side cowling. The DPFE sensor is the rectangular thinging and the hoses come out the bottom of it. They are a couple inches long.