Seasonedveteran
Junior Member
So I'm chasing down a rough idle without a CEL to go along with it. By that I mean you can feel it in the body of the truck, but the RPMs don't really dip, but you can witness the engine actually move, though. While doing my regular Spark plug interval (still running coppers, so 30k) I noticed rust specs on the dielectric grease, and pulled the boot on that coil. My '11 5.7 with 151k on it has the older coils without that small resistor in them, fyi.
Either way the screw inside that recessed plastic standoff is rusted to s***. Subsequently I notice that ALL my coils have the same issue, even the one I replaced in 2021 with the resistor in between the spring and screw, that one was corroded as well, actually.
So, by the looks of it this has been going on for longer than my rough idle...I know these should be replaced, but I'm most concerned about this idle problem and don't want to throw $500 at the truck and not fix that problem first.
Any idea what would have allowed moisture to penetrate the boot and rust all these? Can I just use a Dremel wire wheel to clean those screw heads or does that mean the windings are also likely *****'d, and must be replaced in the pursuit of solving the idle mystery?
I've recently: Seafoamed the intake manifold (with moderate idle improvement), plugs of course, swapped the worst looking 2 coil packs, and smoke tested the evap system and replaced a worn gas cap and vapor canister leak detection pump. The shop also stated my engine mounts and harmonic balancer were in good shape...Oh, and my Throttle body and PCV valve are clean.
This may be my tinfoil hat talking, but the fact the Seafoam helped the issue a bit makes me wonder if the dreaded lifter failure has come my way. I haven't pulled the valve cover off to see, but I wonder if the air gap got closed by carbon and now has been widened a little bit via Seafoam?
Where was I...oh, anyone else run across the coil issue here?
Either way the screw inside that recessed plastic standoff is rusted to s***. Subsequently I notice that ALL my coils have the same issue, even the one I replaced in 2021 with the resistor in between the spring and screw, that one was corroded as well, actually.
So, by the looks of it this has been going on for longer than my rough idle...I know these should be replaced, but I'm most concerned about this idle problem and don't want to throw $500 at the truck and not fix that problem first.
Any idea what would have allowed moisture to penetrate the boot and rust all these? Can I just use a Dremel wire wheel to clean those screw heads or does that mean the windings are also likely *****'d, and must be replaced in the pursuit of solving the idle mystery?
I've recently: Seafoamed the intake manifold (with moderate idle improvement), plugs of course, swapped the worst looking 2 coil packs, and smoke tested the evap system and replaced a worn gas cap and vapor canister leak detection pump. The shop also stated my engine mounts and harmonic balancer were in good shape...Oh, and my Throttle body and PCV valve are clean.
This may be my tinfoil hat talking, but the fact the Seafoam helped the issue a bit makes me wonder if the dreaded lifter failure has come my way. I haven't pulled the valve cover off to see, but I wonder if the air gap got closed by carbon and now has been widened a little bit via Seafoam?
Where was I...oh, anyone else run across the coil issue here?
