Hard Starting Chev Colorado Diesel

Recently, i've had 4 or 5 instances where my [3yr old] chev colorado is hard to start. engine turns over strong, so it's not battery and it takes at least 20 attempts before it eventually starts. engine temp is normal, i didn't flood it, and it otherwise starts on the first turn over. could it be the electronic ignition or some other engine computer on board malfunctioning?? and could the problem be diagnosed by the service center when it mostly doesn't have this problem??

I'm an iddiot when it comes to diesel engines!!