P0401 and P0402

[bigcrunch]

Hi, My 1996 v8 5.0 is giving the following codes at the same time

P0401 Exhaust Gas Recirculation Flow Insufficient
and
P0402 Exhaust Gas Recirculation Flow Excessive

I clear them drive 2 cycles back on.

Any idea before I blindly replace parts that are good?

thanks,,,,

 

[swetrid]

DPFE sensor is bad start there and look over the vacuum hoses.

 

[bigcrunch]

It does not have a DPFE sensor, PFE only.

I checked the EGR valve for operation with hand vaccum pump it holds Vaccumm and causes the engine to stumble at idle when opened.

Checked all lines also.

Did ohm test on vaccum solenoid 36ohm, tolerance is 30-70 so fine.

What else have you guys and gals seen the issue?