Rep Power: 0

1997 Civic EX, manual, 149k miles. Garaged, driven 3-4 days a week. Normally starts in 0.5-2 seconds, but once every week or so, it takes 5-6 seconds to start for a couple starts in a row, sometimes barely starting. Then, back to normal starting. Drives fine once started. Alternator is new, battery and starter were recently checked as ok.

I don't expect to fix this myself, but if I take it to the shop, they'll just do diagnostics and if it's not actively happening, they'll offer to replace stuff as a shot in the dark. They're not going to invest time in it otherwise. Last time, they changed the main relay, which had no effect. It's intermittent, so there's every chance that if it's an issue at home, it won't be when I can get it to the shop a day or two later. My concern is that it eventually stops starting.

I know I'm supposed to hear various things when I turn the ignition on before cranking, but I usually don't hear anything recognizable, even when it starts normally. My dad suggested fuel injector treatment, but I would think an issue there would also affect driving or be more consistent. What's a good approach to resolve this?

 
Rep Power: 221

Check the battery and ground connections

 
Rep Power: 0

Battery was checked - terminals are clean and connected.