Hi folks! My truck start to fail again just like some 25,000 miles ago (fixed in jan/09) I visited the same shope and the same mechanical drive test the truck. The fail is most of the time at 70+ MPH he in the city can not replicate the fail because he can't drive no more than 60-65

The truck hesitate and lack of power at 70+ MPH and he fix it channging cops and plugs.

This time I don't have any code. but the truck feels just like before only not as notorius.

He don't want to change cops because he don;t have any hard data to make the change (no computer code).

I want to test the COPs myself. O'm an electronic engineer and I have scopes, waveform generators and all the stuff i think is needed.

Any of you have any experience?

I think to inyect to a coil a 1khz to 5khz square waveform at 12 VCD and look the output in the scope.

The only problem is I don't have a test probe larger than 500V. How much voltage is in the secondary of the coil?

Thanks for your help!