Took my 03 max to Big O tire for basic service. They did an oil change, alignment, put on 2 new tires, and I had them replace the air filter as well.

immediately upon pulling out I thought something felt “weird” but I was in a hurry and didn’t over analyze. I drive about 10 miles on the highway to my next appointment and when I pull in to park it is obviously running rough......as in it feels like I’m on 5 cylinders rough.

After appointment i pull back out of the space and it’s still running rough but no CEL is on. Then as I pull out into traffic and begin to accelerate I feel and hear it actively missing and the CEL is blinking. I’ve got an OBD reader on my car tied to an app on my phone so I pull up the diagnostic and it shows a “pending” P0305 code cylinder 5 misfire. Meanwhile I’m back at highway speed and CEL has since stopped blinking and remained off. As I pull up to the next red light I clear the codes. Engine still sounds and feels like it’s missing at idle but nothing from the CEL. Light turns green and as I accelerate it’s the same story as before, definitely missing and CEL is blinking again. Pending code P0305 comes up again for misfire in #5

I’m gonna take it back tomorrow and have them look at it again. The timing of this happening immediately post-service is suspicious, but I’m sure that it has happened before that something died at the exact moment of a car being in the shop for something unrelated. The fact that it’s cyl 5 (right on the back corner by the air filter and intake) makes it more suspicious. I swear that I’ve done the air filter before and it didn’t involve much messing around or disassembly back there that could potentially have knocked something loose.

Anything thoughts on what I need to be aware of? Had a convo with the service mgr and I’m gonna take it back to them tomorrow morning if I can’t get it figured out tonight.

​​​​​​​thanks!