Codes help pO2197, p0174 and now a whole bunch more….

Have had EXTENSIVE engine work done at the stealership almost a year ago (they literally had it for 4 months). Even re-bored my cylinders.
Ran fine for about 4 months then started throwing codes. I’ve replaced both upstream sensors, the MAF, new gas cap, radiator flush (replaced water pump intake gasket that they neglected to install).
Still running rough and now throwing even more codes. I’ve had it back to the dealership and they keep finding stuff that’s not actually broken to replace and charge me an arm and a leg (and usually end up forgetting to hook something back up or breaking something else like now my drivers side speakers no longer work from their mishandling of the wires around the code reader slot…long story there…
Anyway, what’s going on, I just want to drive this thing! I’m sure I’ve got well over $26,000 into this vehicle by now in total (obviously not worth that much, about 150,000 miles).
No tubing/hoses disconnected. It had been running mostly fine, now so many cylinders misfiring.
I suspect intake gasket but I don’t know? I think the dealership just doesn’t want to have to tear it apart under the repair warranty.
Thoughts????

 

Sort of sounds like a wiring harness issue with that many different codes and misfires. Did they hook up the correct coil wires to the correct cylinders? Have you double checked the coil plugs are seated fully? Do you recall which spark plugs were used and what they were gapped to?

Edit: i reread your post and saw it was running fine initially. Maybe they 'didn't' seat the connectors properly and you hit a large bump or something and a whole bank come loose?

You could try swapping a coil on one of the cylinders that shows a code, to one that doesn't (like an even numbered cylinder) and see if the code follows the coil?

 

Correct. It seemed 100% fine for maybe 3 months. Then I started getting ONLY p2197 or p0174. (For a couple months…it sort of came and went, about every 3rd trip the code would pop up after I’d clear it and it ran pretty much fine).
It’s only this past week that I’m getting all the other angry codes and it’s really sputtering and I honestly can’t drive it…it seems to be using a small amount of coolant (not leaking on driveway, etc) no obvious leaks but you can smell the coolant smell (also no milky oil or smoking exhaust).
I do have an appointment to have a different shop look at it (not the dealership, because as I said, I think it’s something they just don’t want to rip apart and have to cover under warranty…but I could be wrong. I just want it to work again.

 

Hmm, with the coolant issue, have you ran dye and used a black light to see where the coolant is leaking from? So weird that your entire drivers side bank is throwing misfire codes. Something is off with that bank for sure and the fact that EVERY SINGLE cylinder on that bank is 'bad' makes me believe its electrical. Very weird.

With that said, hopefully nothing is wrong with that head gasket on that side after all the engine work you had done especially now that you mention the coolant issue.

 

I haven’t run any dye. I am bringing it to a non-Toyota shop next week to analyze.
The multiple codes really just started this past week, it has honestly only been the P2197 or P0174 for awhile.
I’m really hoping it IS something related to the extensive work that I’ve already had done at the dealership because it would be covered by their repairs warranty!

 

Ya i'll be curious to see what this other shop says about it.

 

So, the shop replaced an O2 sensor (upstream on passenger side). I had replaced this one about 2-3 months ago but with a cheap China one and also figured, well, maybe I got the wrong one? Ran well with no codes for maybe 20 minutes, threw codes (p2195 & p0171) but it ran great. I didn’t clear the codes. Continued to just drive it—seemed to run great, just wanted to blink like a Christmas tree.
About 5 days later, decided to roll the dice and cleared the codes. Continued to run great for over a week and a half, made many longer and short trips and felt like maybe it just needed a break in period or something. unfortunately, codes returned again yesterday. Unhooked the battery for maybe an hour, codes gone/ran great. Unfortunately, codes and rough idle are now back (p2195 & p0171). Is this just an electrical thing? How can it run perfectly (possibly not 100% power, but no sputter at idle and good gas mileage) and then suddenly run rough and seem to switch back and forth? I don’t know what else to do with this….

 

With my past experience with multiple codes. Its just probably one single defect messing up the computer system.
Our 2018 Highlander posted similar codes. Local mechanic changed so many things until he gave up and sent us to Toyota.
Apparently. It was just the Purge valve causing the problem. Once replaced. Everything was back to normal.

I would probably stop spending money and cut my losses