Ford 4.6 liter misfiring?

Faulty or leaking EGR valve, could be stuck, or needs replacing. Too much air, lean mixture and similar to vacuum leak.

Ford 4.6 Misfire

The EGR code is saying you're getting too much gas or it's not being ignited in full. This could be related to the plugs. Random misfire means a couple of things: You put the boots (or wires) on the wrong cylinders; wrong plugs; loose plugs; wrong gap...of course it could be the distributor (if you have one).

Actually a while back I changed the plugs on an acura rl and got the random misfire codes and the only problem was the plugs itself (platinum autolite)...switched to ngk copper resistor plugs and smooth sailing. Might want to just start over with a fresh set.

1. You need to check those ignition coils. I believe 98 was the first year the 4.6L used individual coils for each plug.

2. Be sure you did not crack or disconnect the hoses leading to the DPFE sensor, which I believe sits on the firewall. Ford EGR valves, unlike those GM digital EGR valves, are very durable and rarely have issues. The DFPE sensor on the other hand...

It sounds to me like either your spark plug wires are touching something metal like your valve covers, or it may be out of timing. another thing I would check would be checking for a vacuume leak, listen for a hissing sound like it is pulling air from somewhere, that could cause it to do that also..

I just replace all the spark plugs and coils. still misfiring.