Struggles to start

I have a 2000 Audi A6 that has been a good car. I notice it really struggles to start but only when it is hot and has been sitting in the sun for a while. I had a new battery put in last year and it doesn’t sound like a low battery starting problem. Could this be the starter?

I’d be more inclined to lean toward too much fuel being injected, assuming by “struggles to start” you mean it cranks fine but just won’t fire.

Thanks! It takes to long to fire. There is also a check engine light on and the Audi people tpld me that it needs a new catalytic converter. Would that have anything to do with the starting?