2001 Z24 won't start in mornings.

So this problem has been happening for a little while. We found it to be my battery, and I replaced it about 1 week ago. I tested my Alternator and it is fine (17v-19v while running)and I replaced my spark plugs last night.

Heres my problem:
When I start my car first thing in the morning, It just won't start up.
The battery is fine, it has more than enough juice. ( i usually do 5 cycles of 5 seconds each before I give up w/o battery even sounding like its about to die.) I have checked all my fuses there all good and in place. If I get a boost, it will start. After my 5th cycle, I can smell the gas so I know gas is being delivered (plus I pump the gas on the last one because I'm usually pissed off).

When I get home from work. The car starts on the first try. Just turn the key and it goes, no waiting for the starter to catch.

This morning the temperature was 10 degrees celceus and after work it was 17 degrees.

If anyone has any ideas before I bring this in to a dealership and pay an arm and a leg to get it fixed, it would be much appreceated. I am completely stumped on this.

(Engine only has 90xxx km on it)

When the ignition is first turned on, do you hear the fuel pump run?

Does the starter actually engage and crank the engine, or spin freely?

Is there ANY popping, backfire, or afterfire while trying to start cold?

When the ignition is first turned on, do you hear the fuel pump run?

Does the starter actually engage and crank the engine, or spin freely?

Is there ANY popping, backfire, or afterfire while trying to start cold?

Yes the fuel pump works.
The starter is turning the engine over
no popping or backfire.
I went to the dealership and they said that it is most likley a sensor that is messed up. They're going to run diagnostics tomorrow and find out what the problem is.