The following events occurred with my 2003 Toyota Corolla.
It was an extremely hot weekend (for Portland OR). The previous couple days were hitting 100 F and the Corolla had sat unused. In the morning we went out to the car and when I put in the key and turned it there was nothing.
Checked the battery and it was fine (if my memory serves me right the electric locks worked, and so did the lights all around).
We pushed it around the corner to a friends garage. He tried doing a diagnostic and it didn’t give any results. Checked the spark plugs and there was not electricity anywhere after the ECM. We swapped out the ECM, but got the same results.
We threw in the towel and had it towed to the Toyota dealership. When they received it the first thing they tried was to put in the key, and sure enough it fired up and started just fine. They ran a diagnostic on both ECM’s successfully with no issues. They couldn’t find anything to diagnose, so they sent it back home.
It has now been running for a couple months fine. Should I be worried about something like this happening again?
Full disclosure: It’s a salvage title with a single reoccurring, issue. In neutral the engine seems to rev higher than necessary. When in in reverse on a cold start it will rev higher and seems to choke, lurching slightly (this is accentuated when there is a significant change in temperature from when it was last started). If I let this continue without giving gas or shifting back to neutral it will get worse and has occasionally died. But is then able to be restarted and drives fine. Not sure if this symptom relates to the events described above.