So this thread is for an interesting little theory that I've had for a while. Everyone who has a 5.0 with a tune on it, pull your #8 plug and pull one other plug on the engine (preferably from the same bank, so let's say pull #5 as well). Post a picture in this thread and identify which plug goes to which cylinder.

What we're looking for is evidence that #8 is running lean which would cause detonation and ultimately lead to piston failure.

I also welcome anyone with a bone stock car to post here as well. Let's see what your #8 plugs look like compared to a tuned car.

Also remember not to pull the plugs after idling for a while. To get a proper read drive the car around a bit and then stop it and pull the plugs.

I will pull my plugs tomorrow and post in this thread so we can all see if there's a common lean condition on tuned 5.0's.

 

Good thinking!

 

This is great!