Runs rough after working on it 2002 Subaru Impreza 2.5rs, 5spd

2002 subaru impreza

I just redid head gaskets, timing belt and components, spark plugs and plug wires, new gaskets all over. It has started sputtering under acceleration, but not deceleration. Its intermittent and seemingly random. Seems to do it more with the heat on for some reason. Once you get up to speed, it runs fine until you accelerate again. I don’t know if its a fuel system issue, or if my catalytic converter is clogged, or if its maybe a timing issue? Everything lined uo perfectly when it was done, new tensioner and belt, as well as all pulleys replaced. There is no check engine light, and no other symptoms other than the injectors have always been a bit noisy. All work mentioned was done 400 kms ago and havent had any other issues.

General rule of thumb if there are no check engine light codes stored then it is mechanical. This can be as simple as a loose vacuum hose or hose clamp on the intake to the ignition timing components or blown head gasket. Since you just did all kinds of work to this beast I would start by double checking EVERYTHING you just did. You should be able to check the head gaskets by using a compression gauge on each cylinder to start. Did you have the heads milled before installing new gaskets? Did you send the heads out and have them checked for cracks before installing? Just a few thoughts in my mind without being able to look at it.