Idle Worse After Plugs and Wires, WWYD?

[adriver]

If the kid did the entire job, I would be thinking its more likely they screwed up the install. I probably missed it, but lets say you checked all the wires and made sure they were all on tight. My guess would be they didn't seat a plug in correctly, and most likely the #8 plug. That or maybe smashed in the tip on install, and again #8 is the goofy one.

What about pulling spark plug wires one at a time, and seeing if there is a difference. If you find one that doesn't change, then its that one cylinder and not all of them.

 

[CMoore711]

My wife’s ‘13 Cadillac ESV is at 110K she babies it, she drives nothing like me. It runs good, but I’ve been collecting belts, filters, new pulleys, and fluids for a good 100K mile maintenance. Cause it’s that time and some of it is preventative while we’re in there.

Part of the list is OEM plug wires which I have and I’ve always ran OEM plug wires; But I haven’t purchased new spark plugs yet. Was going to go OEM 41-162’s, but after reading this leaning towards some NGK’s. I’ve never ran into any issues with NGK’s, but also when OEM is an option that’s typically the route I take.

 

[iamdub]

My wife’s ‘13 Cadillac ESV is at 110K she babies it, she drives nothing like me. It runs good, but I’ve been collecting belts, filters, new pulleys, and fluids for a good 100K mile maintenance. Cause it’s that time and some of it is preventative while we’re in there.

Part of the list is OEM plug wires which I have and I’ve always ran OEM plug wires; But I haven’t purchased new spark plugs yet. Was going to go OEM 41-162’s, but after reading this leaning towards some NGK’s. I’ve never ran into any issues with NGK’s, but also when OEM is an option that’s typically the route I take.

Whatever you get, get them from a trusted source and ensure they aren't counterfeits. I don't know if your Escalade would take the same plug, but, for my '08 LMG, I went with NGK Iridium IX- part #TR5IX, Stock #7397.

 

[Tyrant]

This may come across as heretical, but I run copper plugs in just about everything. Apart from my wife's Jeeps (Pentastar V6 and turbo 4 banger), I've had nothing but trouble with iridium plugs. Swapped to them in my Challenger, idle went to hell and I lost ~2 MPG. Swapped back and the idle was perfect.

I pulled VERY rough Iridiums from my Blown 5.3 (including cylinder 8, which was an OLDER plug and 1/8" longer than 1-7) in favor of copper NGKs and my idle improved there as well.