NGK vs Autlite thoughts and a weird issue

[kurthb]

2009, bought used at 111K miles.

Changed the plugs to copper Autolite, no issues. (Autolites looked great and saved them)

Thinking NGK's were the way to go, swapped out the Autolite for NGK (copper)

Started a weird symptom, when cold, it acts like it is starting in 3rd gear with a sprinkle of a ignition miss.

Think it is purely coincidental as my thoughts are if there was an issue with plugs it wouldn't be a bog down issue nor would it do it only for a few seconds when cold.

No check engine light, will have to scan to see if there are any pending codes.

Question is, opinion on NGK vs Autolite? I have had excellent luck historically with both in all sorts of different vehicles.

*I may just swap them back to the Autolites just to see if problem follows

[Deano]

In my opinion, assuming both are the correct plug for the engine and year, then no difference in the plugs. I would wager that the real problem is with the coil pack that is slowly failing. I've had the coil pack die on my former 2009 Wave, and I've had the coil pack die on my present 2009 Aveo. They don't last forever. I am getting good at replacing them. I keep a brand new spare coil pack in the trunk, just in case. Cheap insurance.

Then again, it could be the engine wiring harness to chassis ground connection beside the underhood ECM that is corroded. A bad ground connection here can cause a whole host of strange driveability problems. Such as what you described. Have you ever checked and cleaned that ground connection?

Deano

[Eg.h2o]

I’ve run both. Personally I like the NGK copper best, but I have no real data to say why.

[kurthb]

Just after posting this, I had a CEL. Complained about the upstream 02 sensor, just replaced it and so far do good, but too early to say that was it. I was starting to think throttle body.