1999 7.4L missing due to burned plug wires

[LikeABoat]

Putting this out there to hopefully help others. Just replaced the plug wires ( and plugs ) for the 3rd time in 2 years. Will run great and then start to have a miss that seems to start at idle and then really shows up while at low RPM's in OD and slightly tipping in to the throttle. I've made sure that all wires were away from exhaust and paid special attention around the EGR pipe ( this was my original problem ). The boots at the plugs seem to be getting to hot and failing. THis last time it was #1, I pulled the boot and the plug was covered in black soot. So, I bit the bullet and bought $200 Accel ceramic boot plug wires ( and new plugs again ) that are supposed to be good for 2000 degrees. Its running like a top again. We'll see over time if they hold up.

 

[movietvet]

Pics of the area please. Both sides

 

[Schurkey]

Yup. Kinda suspecting that the OEM spark plug heat shields have rotted and fallen off.

Some of the spark plug heat shields on my '97 7.4L have mysteriously disappeared due to the bolt-hole rusting away from the body of the heat shield.
www.amazon.com/GM-Genuine-Parts-10166846-Shield/dp/B098BR8CXN/ref=sr_1_31?

 

[Supercharged111]

In addition to the factory shields, you can slide some wire harness insulation over the boots to make them last longer. Only 454 boot I've legitimately roached though had the factory heat shield fall off, but that engine is supercharged so really gets those exhaust manifolds cooking.

 

[454cid]

I've never had burned boots and half my shields fell off years ago. I am in mostly cooler weather and tow very little though. When I did wires last, I replaced the missing shields with LS style shields. They just slide over the boots, so no fighting rusty hardware.

 

[LikeABoat]

In addition to the factory shields, you can slide some wire harness insulation over the boots to make them last longer. Only 454 boot I've legitimately roached though had the factory heat shield fall off, but that engine is supercharged so really gets those exhaust manifolds cooking.

I have heat shield on all the wires near the EGR pipe. It’s missing some shields but the latest failure was with a factory shield. LS style shield would have been another good idea.