Funky Chevy idle surge
Owners of 2010-2011 Chevy Colorado or GMC Canyon vehicles equipped with the 2.9L 4-cylinder or 3.7L 5-cylinder engine may complain about a cold start idle surge condition. The surge will be accompanied by erratic exhaust CMP angle readings in the CMP data list on the scan tool.
1. Visually inspect the wiring and connections to the CMP actuator solenoid valve.
2. If the wiring and connections are OK, remove the solenoid valve.
3. Inspect the valve inlet screens for evidence of damage or debris.
4. Inspect the valve bore (in the cylinder head) for evidence of debris.
5. Install a new CMP actuator solenoid valve and try to repeat the cold start idle surge condition. Make sure that the vehicle sits for a full eight hours prior to restarting.
6. If the concern is not fixed, drop the oil pan and inspect the oil pump pick-up feed tube for restriction or blockage.