Anybody good at reading plugs?

Highly possible. The engine didn’t SEEM to have a miss, but it would be great if that was the only issue. If it was, I should see a pretty solid improvement in mpg, and the new plugs should all look good correct? If the mpgs remain approximately identical to before changing the plugs, and one cylinder still looks like it may be a little rich, then it likely wasn’t the plugs that trashed the cat, and points more toward injectors, yes?

 

What im saying is, get a little code reader that can show some basic data. if the long term fuel trims are stable/close to zero, forget about rich or lean. The fuel system has good control. This information would also be helpful in regards to your fuel mileage. If the trims are stable then you can rule out a fuel injection issue and start looking at mechanical stuff like tire size, weight, aerodynamics, etc.

I dont see many injector failures that harm converters, maybe if it was stuck wide open and leaking badly but thats rare. The more common scenario is a loss of spark from crappy old plugs. That is what allows liquid unburned fuel into the exhaust.

Again, liquid unburned fuel is not the same as a rich mixture.

To summarize.. if you're worried about the mixture, get access to some fuel trim data. If you're worried about damaging the cats, keep the secondary ignition components (plugs, coils) in good working condition

 

^^^ sounds like a good plan, and makes plenty of sense. Any recommendations on a code reader?

 

Cheapest one at the local parts store, just make sure it has some basic (obd2) data and not just code read/clear

 

You’re welcome.

There’s a link in my sig to get a digital version of your Owners Manual. I find it immensely helpful to have it on my phone (Apple- Books Library). Makes searching a breeze and cutting/pasting almost effortless.

 

I have the earlier version of this OBDLink MX and love it. App on your smartphone, realtime data acquisition, and it will read/clear error codes. For $10 extra it will connect to other controllers including ABS which was useful in finding which wheel speed sensor failed.

https://www.scantool.net/obdlink-mxp/

 

What sort of LTFT values should concern me?

 

Anything over 10%

 

Looking at 3.4% and 7.0%. Zero misfires. It stays in closed loop for quite a while, and will drop from open loop back to closed loop if I get stuck at a traffic light. Many of my trips 5-10 minute trips never get it out of closed loop. Not sure if that’s completely normal or not.

 

Is the coolant temp getting up to 190?

 

Yep. Very rapidly.

 

I dont see anything that would cause me concern. You got the old plugs out of there, the fuel trims are fairly stable, its not detecting any misfires.

Drive it, enjoy it, keep an eye on the data..