I replaced all six spark plugs in my 2003 Pilot even though it was not running bad. I have 230k miles and plugs have not been changed in about 120k miles. After a straightforward replacement of the plugs, I am now getting consistent misfiring of cylinders #3 and #5. I put one of the old plugs back in #5 and no change in misfire. I expected the Pilot to run like a top with new plugs, but don't know what's going on. Anyone ever experience anything like this?