I bought a 2006 Buick Rendezvous (automatic transmission, 3.5L, currently 80k miles bought at 77k) in April of this year and in June, I started having intermittent issues starting it up. It happened, and continues to happen, about every 3 weeks, approximately. Thankfully, and I don't want to jinx it, I've never had a problem starting it in the morning or after work. The only time it seems to have trouble is on that weird 3 week-ish cycle, and only after short trips, 10-15 minutes driving to the grocery store and less than an hour inside. I thought it was a fluke at first but by September, I got worried enough to take it into a shop. I explained the issue and the mechanic looked it over in about 30 minutes or so. On the receipt, next to my concerns, he noted "possible fuel pump, throttle body, ECM and/or wiring issue", and under Service Description, it says, "perform module scan no codes ck tsbs". He said he didn't find any issues and of course, it started up fine for him each time he tried. My teachable moment in this is that I should have directly clarified what he inspected because I'm not sure if his notes mean that he checked the possible issues he identified, or if that is some bigger, complex task outside of a cursory inspection. Either way, I transitioned seamlessly into wishful thinking and convinced myself there wasn't a problem at all, maybe it was user error somehow.

Of course, it keeps happening pretty much on schedule. When it happens, the engine turns over and it sounds like it's trying to start, it just doesn't make it. Until it eventually does, and then it runs fine. Until now it's taken maybe 6 attempts max to get it going, but last night I lost count. At one point I thought it wasn't going to start up at all and had roadside assistance dialed but gave it a few more tries and it eventually got going after about 10 minutes total of trying. I took a video for the first few minutes of the process to try to gather more information about what this looks/sounds like when it's happening, since it wasn't happening for the mechanic. (My cringy ad-libbing is awful, I hardly noticed at the time of recording...just operating out of pure frustration).

My plan is to take it to a different shop and I'm hoping that the video will provide a bit more info for them. I would be so grateful though if anyone is willing to help educate me about the potential issues so I can continue this process as informed as possible. I'm wondering what the other mechanic might have missed regarding the notes on his receipt, or anything else that he wasn't considering, and how to prevent that for my next service!