I've a 2010 Chevy Cobalt LT/2.2L. CEL came on 2-3 weeks ago. Constant 1 week, then intermittent. Codes P0010 (intake actuator solenoid), & P0326/27 (knock sensors). Hubby replaced intake solenoid, CEL cleared after 3 starts, then came back on, intermittently. (CEL back on constant after dealer cleared codes 2 days ago). Pulled codes again: POO10 again and P0013 (exhaust actuator solenoid) & PO326/27 (knock sensors). Since the POO10 pulled again, does that mean the fix didn't work or could it be something else like camshaft position sensor? What is my next best bet: replace exhaust solenoid or sensor or even knock sensors or other route? Should I first test their ohms and check for wiring/corrosion issues? How do I check for that and can sensor ohms and knock sensors be tested? Anyone have a link? I called the dealer and they couldn't give me advice. for my last oil change, the mechanic said i had dirty oil/sludge. Does that mean i could have corrosion/poor oil flow to actuator connector or what else? Do I just clean the connector. Please help. I am clueless. Finally, sort of a ticking or clicking sound is coming from my driver door area when I drive. (since dealer cleared codes & programmed my key fob 2 days ago). Would a timing chain issue present that way and could timing chain throw the above 4 codes?