I just had my car tuned up less than 4K miles and it has been missing and bucking especially in the morning and worse when warm or humid. Just brought it back and after 2 days they can find nothing wrong! Of course when I brought it back it has been cool and dry so it runs much better in this weather. He said bring it back again when it is acting up. I remember that the wires arc and something about spraying on something to fix this>? The owner did not relate to my comments. It is a 1999 Safari van GMC V6. Runs good normally until this. 130k miles. Tom R.