Rep Power: 0

Son has 2011 Civic, 1.8 engine. Maybe 2013, not sure, to be honest.
In his wisdom, with YouTube guidance, he did valve cover gasket replacement. Last Friday, I believe.
Car appeared to be doing OK. It was his first real DIY job. Guess, he felt brave.
So you know how tight access is to the back of the valve cover.
He texts me today and says that while on FWY, engine sputtered for brief moment. Then some time later, it was hard to start and CEL started blinking.
He shut it down started again - all was good.
So that tells me, he has loose something somewhere.
No codes stored.
I always go to the last job done, in case like this.
That in mind - what is that he possibly dislodged or didn't connect well doing the gasket?
All plugs are 2 weeks old. It all started with misfire in cyl 2, then we found oil in the plug well, so he did the gasket.

Thank you.

 
Rep Power: 244

Blinking CEL indicates a misfire so it’s possible something is not tight or sealed properly. I would pull the plugs and see how they look to get a better idea of what could be causing the misfire.

 
Rep Power: 229

I had a similar problem once when I left a coil pack half clipped together; everything looked like it was correct, took a while to find, lol.


-make sure battery terminals are tight
-disconnect all related electrical connections and reconnect
-if any ground wires were removed check for tightness