.45fats

I'll jump right in:

I have an 04 f150 that I got ahold of with 240K miles on it, I also got an 05 5.4 with 40K miles. We did a one for one swap, also replaced the o2 sensors while we had it all out. The only problem I'm getting now is when under load or periodically at highway speeds (65+ over 2200 rpm) it will begin pinging.

only issue I can find is intermittently it will through an error for bank 1 or bank 2 or both at once running rich.

I'm kind alost and I know I'm probably missing something simple or stupid, so if anyone has any suggestions I cna put into practice I would appreciate it.

thanks

primalurges

If it's running rich you can confirm by pulling plugs. You likely have bad plugs or coils or both. The pinging is likely unburnt gas igniting whenever the coils or plugs or both muster up a big enough spark. It will probably be as simple as that especially with te mileage you have and I'm guess lack of PO's service history.

.45fats

Would a bag plugs and/or coils not show up when it's revving but not under load? also what's the best way to check this? not looking forward to replacing $60+ per cylinder not to mention the apparent threat of easy to break plugs without some plan for testing...and I admit I don't know where to start with that one.

primalurges

ebay has aftermarket coil sets for about $70 all 8. However before you spend a penny on that you need to at least pull one plug out to check for condition. Of its bad they'll all be bad. If they're good I'd go with the coils.

EBC-150

This may seem 'off the wall', but here goes...If your vacuum check valves are bad for the 4WD system, the IWE's can slightly engage under engine load conditions (low vacuum) and sound JUST like the tell-tale metallic 'marbles in a can' of detonation. Try doing a run in 2WD and get the pinging, then do the same run in 4WD, and see if the noise disappears.