Need to find out how you can tell if your COP is good or bad. I have a 98, 5.4 that has a miss under mild acceleration, but idle is perfect. If I am running along at anytime, and I accelerate at all, a miss and shake takes place. I have removed all of the coils, and did an OHM check, they are all in spec. .5 across the terminals and 5.5 from one of the terminals to the plug spring in the boot. Approx. Under drag acceleration, I do not feel a miss, but it doesn't pull like it should. Like maybe all 8 are not firing.
One thing I did was remove the elec connection to the COP, start the engine, and rev it up from idle. I can tell that a plug is not firing. I did this to all 8 with the same results. Even with all COP's connected, and I rev it up, it does not rev smooth. So I am thinking that at idle the COP is fine, but rev the eng and the COP breaks down.
All new Motorcraft plugs.
What can be done to test the coils? I really don't want to buy a whole new set of coils, if there is another reason for the miss.

 

Here is some things I have done. Replaced the following with used parts. Throttle body, EGR valve, EGR vacuum regulater, idle air control valve, camshaft position sensor, mass airflow sensor and air temp sensor. All off these actions did not change a thing. Also no codes have shown up

 

there really isnt a "test" for the coils. If you want to find witch one is bad you either wait for the engine to set a missfire code and retrieve it or you need a scanner that sees the live engine data or mode 6 Dealers have them and most smaller shops do to. Rarely free though.

 

Thanks jethat. I might have to pay to get it checked. I'll replace the injectors next with a good set I have. Have to think about this problem some more.

 

There's been SO MUCH info posted on this subject in the last couple weeks... - Not sure how anyone could miss it lol.

 

because common sense is simply ignored as everyone is re-inventing the wheel

 

Sorry. I should have looked more.