The Nissan Path

Hey everyone. Just thought I'd get everyone's opinions about my issue.

When my engine is cold, it starts up just fine (maybe even quicker than normal). But when it's warm, it takes a few extra seconds to start. I have to hold the key when I turn it a few seconds more. Kinda like the battery was dead. But I went to an O'Reilly's Auto Parts and got the battery, starter and alternator tested and all were good. I recently had a tune up done and a bad fuel injector replaced.

Just wanted to pick some brains on here. Thanks everyone. Loving being a new Pathfinder owner!

Could be the fuel filter, which is really cheap and easy to fix, so you could start with that. But it could also be the fuel pump, or something else that I don't know about.