What's going on with these plugs? HELP ASAP

[DrTorque]

I've got a customer with a '87 5.0 on my dyno right now. He came in running very rich, and he lowered his fuel pressure. The A/F is good right now. He got his best power at 246, but then the power started dropping like crazy (246, 225, 196) even though he wasn't making any more changes. I thought the distributor might be slipping, that wasn't the case. I had him pull some plugs. They look like this:

The richness obviously explains the soot, but what about that corroded spot? Is it arcing there? Any explanations for the dramatic loss in power?

They're gapped at .040, and I realize they should be a little more, but I can't believe that would have a major effect.

 

[shttygtstang]

wow theres somtin realy fuced on that car huh

 

[Schlodes]

Did some or one of the parts of the ingition system kick the bucket? A plug wire ... coil going south... does it have an aftermarket IGN box? Try bypassing it.... running the stock IGN..

 

[DirtyD916]

how old were the plugs?

 

[Ranchero5.0]

I'd run a compression check to be sure he didn't lose a head gasket. Then go over the electronics and check connections.

Jamie