Engine Diagnostics

Hi guys,

I've been having some hard starts on my new Tacoma (33K miles) and I'm trying to figure out what the issue is. I have not changed the spark plugs and they are factory plugs. I also have checked the battery and alternator and those have come up fine - although I understand checking voltage is an unreliable way to check the battery. The battery is also original stock.

Someone told me to run an engine diagnostic on it.
Don't you have to have a check light for that to be effective? I would imagine that the engine needs to have a code in order to read it and if a code was there I would have a light for it right?

The issue is just that the truck cranks a little longer than it should every now and then before it starts. I've not been able to find a trend quite yet. Temperature or weather doesn't seem to effect it. But it usually just happens when the truck has been sitting for a while. It also isn't terribly often. Maybe once every 1-2 weeks. Long cranks are usually 2-3 seconds.