Check your Coil wire. A similar thing happened to me. The coil wire
touching the intake plenum caused a short or spark when they touched. After
replacing the plug wire set, which includes a coil wire, the problem went
away
wrote in message
>I have a 97 4runner with about 200+ on it.
>
>
> The question I have is that I have had to replace the Number 2 Coil
> pack about once every three months. I have done this about 2 times now
> and it is getting time to do it again. I would like to fix it for good
> this time since I have the time to do it and another car to drive
> while I get it fixed or poke around at it more.
>
> After about 2 months with the new coil pack this will happen. When I
> start the truck in the morning it runs really rough. Like it is
> running on only 5 cylinders instead of 6. After about 30 seconds to 2
> minutes it runs smooth.
>
> Right near the 3-month mark. It will not run smooth until about the
> five minute mark and you can here it miss every once and awhile at an
> idle thereafter.
>
> The out come is always the same the Check engine light comes on and my
> reader always says it is misfire on one of the cylinders. What happens
> is that the cylinder that the Coil pack sits on misfires but the
> opposite cylinder will fire with the same coil pack.
>
> I have tested the coil pack by putting it on a different cylinder and
> reset the ECU. Same thing happens Check Engine light comes on after a
> short time but the misfired cylinder moves to where ever I moved the
> coil pack. So I know the coil pack is bad but just cannot figure out
> why it is always the same one and how to prevent it from burning out
> after another three months.
>
>> Stay informed about: Strange Coil pack issue