The old girl, 92 3.9 vse lpg, is being a little temperamental at the mo. Turns over,fires, but does'nt want to start. Think its the cold and the damp. Cleaned the plugs and lots WD40 but still won't play, so ordered some more plugs off Flea-bay. Plugs in the car at the mo are Champion RN9 4YY. The ones I hastily ordered (silly price) are RN9 Y4C. Will they fit or have I just wasted £2.90 ( 10 plugs).