Contour Enthusiasts Group Archives Forums Modifications Duratec Maintenance OBD I codes 551, 332

I've been battling my Check Engine light off and on for the last 7 years or so, but I always seem to get the same codes when I check them myself:

551 (hard fault) - Problem in Intake Manifold Runner Control (IMRC) solenoid/circuit

332 (memory fault) - EGR did not open/respond during test or if memory code, did not open intermittantly

I cleared them, drove just a little bit, the CEL came back on within 2 miles and I have the same codes again. The CEL is not constantly illuminated, comes off and on, but seems to stay off the longer I drive. (I live a mile from work, and for the last 2 years, have been punishing my engine but not always letting it get fully warmed up)

My engine has also developed the annoying habit at idle of racing back and forth between 500 and 1000 RPM, about once per second. Often, while cold, I have a serious hesitation/lack of power which approaches stalling, that I can overcome by revving over 3K to get rolling. It feels like something is plugged or not opening up.

I'm sure my dealer has pulled these codes at some point but didn't offer any corrections.

any thoughts as to what may be wrong, and/or how to remedy it?

thanks. [car is just about 9 years old and has 76K miles on it]