egr valve issues

[heavymtl]

whats up peeps....i keep getting code P0401 setting....it says (EGR SYSTEM FLOW INSUFFICIENT)....i have taken the egr valve off...cleaned it best i can..and still have this issue....could it be bad and set this code? and not set some other type of code?...now for a little background info....it's on a 96 pontiac grand prix se...3100 sfi motor...i recently had some tranny work done...and i have had to replace the thermostat...that was a bear to do (had to do alot to get to thermostat)...one thing i noticed for a long time....my egr valve pipe had a small hole...that means a small exhaust leak...when ever i needed to move that pipe the sound got louder...so i pulled a pipe from a car at the junk yard...it works and i have quiet exhaust....could that hole i had for a long time have made something worse?....anyway there is something to think about for you all ...peaceeeeeeeeeeeeeeee

[gectek]

prob a bad egr...maybe a plugged egr port on the exhaust side or the part into the UIM...or maybe a bad MAP signal, because that is what the comp uses to determine if there is sufficient egr flow IIRC

[IsaacHayes]

Take the EGR off, and get a thick wire or maybe even coat hanger and some carb cleaner. You might want to take the throttle body off too so you can get the other side and see what you are doing.

Spray carb cleaner in the plenum/upper intake manifold where the egr gases go into. Work the wire from both sides to clean it out.

That is what usually clogs. The EGR may open & working, but if the plenum is clogged it won't go in there, and the computer can tell this by reading the change in the MAP sensor knowing if gasses are coming in or not.