Saturn Vue 2008 check engine light on, Multiple codes: P0018 0036, 0054, 0138, 0140,& P0141
SATURN Vue '08, FWD 90K Miles, check engine light on intermittently over 3 yrs.
Occasional loss of fuel efficiency noticed. Multiple codes [o2 Sensors]. Regular mechanic advised it may be mostly P0018 Crank to Intake correlation, possible Timing chain [warranty]. Advise take it to dealer. [Really?]
Multiple codes: P0018 P0036, P0054, P0138, P0140,& P0141
Help please tks. Zeus