Early morning motorboat sound

'95 Civic, 225k, .5 fuel injected, A/T . . . we’ve had a lot of rain lately . . . last few mornings when I started the Civic after an overnight rain the engine started right up but putt-putted like a motorboat for a few seconds . . no more than 5-6 seconds, then cleared-up and ran smooth all day. Last night it didn’t rain and it started without the motorboat effect. New plugs and wires (within 5k) . . . I’m thinking cap and rotor (has about 40k on cap and rotor). Comments? Ignition issue or fuel? Thanks folks! Rocketman

When you replaced plugs and wires did you use OEM or aftermarket? Cap and rotor might be needed but if you used aftermarket wires they could be suspect as well.

Did you use dialectric grease on the wire boots? It seals up the boots from moisture/humidity.