This MIGHT be the fix for you. I've mentioned this before for others and may seem to simple BUT--be sure the Plugs were gapped at .028 to .030 before being installed,most plugs come out of the box at around .040-.045 which is to much of a gap for the Rio. Also the plug wires are all bunched up together, I had a mis-fire problem and being sure the were dry sprayed them with silicone solved that problem. Give it a try,it might be a free fix. BTW The thickness of the average credit card is .030 so you can use that to set your plugs, don't even need to buy a gauge.
Last edited by jcwit; 08-20-2008 at 03:59 PM.