help p0401

[Paul_A]

All I can say is I had 401 persistently.... no matter what I did. New egr, cleaned the pipes, new gasket... everything I could think of..... turned out to be... yep ... intake manifold gaskets. Why the 401 though?? doesn't make sense

[89Vette]

I bet the MAP is in the intake...and the bad intake gaskets affected pressure readings during the EGR cycle.

Another thing to consider is a wiring problem for the EGR/MAP sensor. Any intermittent connection to those sensors would cause an issue.

[zadam123]

All I can say is I had 401 persistently.... no matter what I did. New egr, cleaned the pipes, new gasket... everything I could think of..... turned out to be... yep ... intake manifold gaskets. Why the 401 though?? doesn't make sense

how did you find out it was that?