Having a misfire condition. Autozone read the code and it is a misfire on #2.

The misfire comes and goes. If I do highway driving is goes aways ans stays away for a few days. Comes back after a couple days of city driving.

Plugs, wires and fule filter have 10,000. Platinum plugs and good NAPA wires.

What are the possbile causes and how do I isolate it.

 

Ok Monday morning forgot a few things. Its a 1998 F150 Suppercab with a 4.6L 99,000miles 2wd auto.

 

First, don't bank on 10,000 mile for no ignition faults.
It can still be a wire, or boot if it comes and goes and the plug.
Change the plug using Motorcraft and change out one item at a time or the whole chain.
Look for any coolant leak in that area.
Then if you still have the action, the coil pak is suspect.
This is when an engine analyzer will tell the fault real fast.

 

Last night I pulled #2 plug. Gap was within specs. The plug was clean and show no signs of fouling. Check for spark at plug- ok.

Yesterday it was missfiring badly and the service engine light flashed a lot. Today I could still feel a slight misfire and the light started flashing after about 20 minutes of driving.


What next?