That would be because the 551 code refers to the secondary intake runner control valve, not the idle air control valve. Here is the
DaliDesign.com description:
551 Problem in Intake Manifold Runner Control (IMRC) solenoid/circuit
You should check that the electrical connector is attached to the solenoid valve on the center of the intake's rear plenum. Your secondary intake runners are not closing and below 3,950 rpm the torque output of the engine is being reduced by a good 25 lb-ft below that rpm.
And, Jim, please release the "Caps Lock" key. It looks like you are yelling at us.
<small>[ January 04, 2004, 09:07 PM: Message edited by: sdpatt ]</small>