Now that you clarified a bit more..............the car wouldn't start because the plugs were wet, with time the wet evaporated but not ever 100% so the car starts later but has a faulty idle as the plugs are still fouled, they convert from a wetfoul to dryfoul as the fuel then carbons up the side of plug with a now dry deposit that then shorts out the same way as before but not bad enough so that it now starts but does not idle right.
New plugs will cure the idle if that is all that is now wrong. If still doing it then vacuum leak likely.
Old plugs coming out dark verify what I said about plugs. You can clean old to work like new again but needs to glassbead to do it, no washing on earth will clean that deposit off the porcelain.
If you have access to realworld OBD live data the first O2 will be hanging low at idle when the engine is doing the lumpy idle, the sensor not going over .5 volt is a lean indicator of a vacuum leak.