2005 Nissan Altima. Intermittently crank but not catch, helps when I give it gas?



Starting about a month ago I noticed rough idling, engine knocking when I started it, and some acceleration issues. I let it go until I turned my key and it cranked, but didn’t catch. Seemed to help when I would give it gas when cranking, though if it had already failed to catch even that wouldn’t help until randomly, hours later, it would start …

Sent it to the shop, they found a catalytic converter code and they replaced plugs and coils ($400) and it was fine for about 3 days -no more rough idle and it didn’t need to press the throttle to catch- when the check engine light came back on with the following codes:

P0420 catalyst system efficiency below threshold
P1612 nats malfunction (security system)
U1001 invalid or missing data for primary ID
U 1000 Lost communication with ECM
P0462 Fuel level sensor circuit low input
P0463 fuel level sensor circuit high input

Today it failed to start on the first go around (crank but not catch) but started after I gave it gas. Still dealing with rough idle.

It seems to start fine without giving it gas if the engine is hot. Mechanic last week seemed to think it wasn’t fuel pump, thought that the plugs and coils was the issue and not catalytic converter, but who knows…

Any idea what this could be? I’m stumped.