I picked up an 03 v6 as a first ride for my kid. It’s got a noticeable lack of acceleration (beyond just a normal v6 - something’s wrong). Car runs fine once it gets up to speed.

Tranny rebuilt by transmission shop.

Changed plugs (wires looked good).

Changed fuel filter.

Air filter looks brand new.

Installed brand new battery.

Previous owner deleted cats.

Motor sounds good and runs smooth.

No engine codes.

131000 miles.

Could a weak coil pack do this and NOT send an engine code?

How about something internal like a stretched timing belt/chain?

Would bad/old 02 sensors do this and not throw a code?

Going to use a stethoscope and make sure all injectors are clicking. I don’t really sense any kind of miss.

Old plugs were slightly oil fouled but it was leaking from valve covers which I addressed. Plugs smelled of gas.

Brakes redone (not stuck).

Thoughts? Thanks!