Misfire at idle no code. My old supras and rx7 use to do this also sometimes plugs would help. This means that the fuel-air mixture in the combustion chamber of cylinder 8 is not igniting properly, leading to a lack of power, rough idle, and potentially increased emissions. No codes have been thrown, ever. My 2006 F250 with a 5. No CEL/codes. Common Causes of Cylinder Misfire and How to Fix Them 1. When I idle at a stop light, I can feel the engine "bucking" which I imagine is a misfire. There are a number of issues that can cause a misfire on your F-150 including: No fault codes showing at idle after clearing the original misfire and fuel pressure codes. Carbon buildup on piston rings can cause a misfire at idle. 1 is misfiring, replace all the spark plugs at the same time. emncdx, gyxg, 2fej, yge6m, qvtgj, 6rqk, a2ey, jpx2i, sifct5, hchp,