1997 Xlt 5.0 engine miss

[changetires]

I have a 1997 Xlt 5.0. The thing started running rough so a trip to Firestone and 1000 dollars later the engine was somewhat better but still rough. Had them take off the crappy wires they put on and had them put on Ford original wires from dealership ran great for a week then a smaller miss started happening. Regapped plugs which were also from the dealer. Ran smooth for a few days now its missed all the way to work. Have replaced the O2 sensors. STill nothing

HELP!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

[jimbo74]

i would take it somewhere else, it seems that the place you are using may not know what they are doing..... it sounds possible that the wires, plugs might have been attached to the wrong destinations..... also, what condition is your coil pack in? you may need to get that tested....

 

[dogfriend]

I second testing the coil pack. I recently replaced mine because the secondary resistance was too high and it would miss under load.

The Haynes manual has a good section on testing the coil pack(s).

 

[changetires]

Thanks for the help, but what is the way to check the coil pack as per the book. Would like to try this first before buying the book. Thanks again

 

[dogfriend]

To check the secondary resistance of the coil pack, you test the resistance between the appropriate coil towers ( e.g. 1&5 on the V6 because Cyl 1 and Cyl 5 share the same coil). The resistance should be between 6.5 - 11.5 kohms for each coil. More about it in this thread:Coil Pack Testing

For a V8, you have two coil packs but it works the same way, two cylinders share each coil, so you need to test the resistance of each set.

 

[james t]

i vote a coilpack too. depending on mileage, it may be time to just replace them both. just out of curiosity, what did they do/replace that was $1000?