97 awd 5.0 code 402 runs rough

[moonshinehd]

my explorer runs rough, check engine light is on pulled a pending code 402 with a reader. pulled vacuum hose off egr, no vacuum present, runs very rough and dies. is this the dpfe sensor or a solenoid or something else? any thoughts.its a 1997 awd 5.0 v8 110,000 miles

 

[jremington59]

Do you have the 96 engine with the internal egr?

 

[moonshinehd]

I don't think so I can see the egr valve on the rear driver side of the engine.

 

[moonshinehd]

the egr valve is on the passenger rear side not driver side

 

[Turdle]

Is there a 1" (or so) diameter metal tube going from the passenger exhaust manifold to the egr valve?

If so, you might try a DPFE sensor, then the rear 02 sensor before replacing the cat

Also, any leaking from the tube or manifold may cause a low flow egr code.

 

[moonshinehd]

I have a excessive exhaust gas flow code.

 

[moonshinehd]

I"m thinking maybe upper intake gasket leak, took off egr valve, plugged it and no change in running. also hear a possible hiss sound coming from upper intake area.

 

[jremington59]

Do you have an EGR tube on the passenger side going down to the manifold?

 

[moonshinehd]

yes there is a tube to the exhaust

 

[jremington59]

There are generally three parts to the EGR system: the EGR valve, an actuator solenoid, and a differential pressure sensor (DPF). These things work together to deliver the correct amount of recirculation based on engine temperature, load, etc. The P0402 code means that OBD detected an excessive amount of EGR.

Symptoms

You may notice drivability problems such as the engine may surge off idle. There may also be other symptoms.

Causes

A code P0402 most likely means one or more of the following has happened:
•The DPFE (differential pressure) sensor is faulty and needs to be replaced
•There is a blockage in the EGR (most likely carbon buildup)
•The EGR valve is faulty
•The EGR valve may not be opening due to a lack of vaccuum

Possible Solutions

With a P0402, it is common for people to replace the EGR valve, only to have the problem return. The most likely solution is to replace the DPFE sensor.
•Check the voltage at the DPFE sensor both at idle and when the EGR is open
•Replace the DPFE sensor