Just checking about which iridium spark plugs to use in my truck. I installed AC Delco 41-162 plugs based on Summit Racing & Parts Geek websites but other sites say they aren’t a fit. Engine runs fine but gas mileage stayed about average. I changed plugs & wires around 97k miles. AC Delco 41-985 iridium plugs were in the engine from factory. Any one know of any issues?