What else can GMC-Dealer or I check: 61,000 mi, 2007 Canyon with new Plugs & battery? RAndom intermittent, few days to weeks will not fire-up: no gas smell, cannot re-set igntion, two times in to GMC DEaler and charged for (no info on computer & starts OK at dealer), no coughing of engine or firing, no change in pumping gas pedal or holding to floor(1 trial), and will start after "several minutes to approx 30 minutes!!
Intermittent Problems Are Tough. It Sounds To Me Like Possibly The Security System Gets “Confused” And Thinks You Are Trying To Steal Your Own Car. I Wonder If It’s Disabling The Fuel Injectors ?
Is there anything different in terms of dashboard lights when it won’t start, like the “security” light acting differently ?
GM does have a general bulletin covering electrical problems related to “fretting” corrosion in electrical connectors for a myriad of different control modules (There are a dozen plus) in the vehicle. Has the dealer tried unplugging and replugging in the connector(s) to the module(s) that would relate to this starting issue ? Sometimes that will give a better connection if it’s intermittent.
The more permanent fix is to brush the pins inside the connector with a nylon bristle brush and then apply dielectric grease to prevent future corrosion.
How big is your dealer ? I sometimes recommend that people go online and get phone numbers for large, high vehicle volume dealers, and talk directly to the Service Manager or Service Director there. I’d call several. Large dealers often see problems more frequently and are more familiar with them than smaller dealers. You may get some ideas on what to check / have checked. You may see a pattern developing after getting several more opinions.
2007 GMC Canyon (4-Cyl); may have started with increased “cranking” times, wespecially after short runs at approx 50,000 mi(3 yr). Fuel filter was replace at at 25,000 mi and change to K & N Filter also then: to wit it seemed to take “several;” times of cranking to get it to fire & run in early times, thogh I did get it to fire-up twice with pumping gas peda(!).