Once you verify the firing order is correct, verify that you have the wires fully seated to your coil packs, and onto the spark plugs. The rear bank is kinda tough to access, so having the plug wire not fully seated is most common. Its happened to me before. Also, sometimes techs will swap coils, so the numbers on them no longer correlate to the cylinders. I hate it when they do that, because it makes diag that much harder.
Saturday, September 14th, 2013 AT 6:54 PM