I put new plugs in my 93 Ranger with a 3.0 and 217k on it and now I have a slight miss. My wires are not very old and I am not sure how old my cap and rotor button are. The miss is slight and only occurs at slight peddle or when I am under a slight strain b4 shifting gears. I did discover a couple of small cracks in my plug boots and wrapped them well with electrical tape but Im not sure if this is a good fix. Thank you for any info.