Sometimes on my discovery when I go to start it, it'll crank and then stop and then crank again. Also, it cranks longer then it should. I checked the battery it's clean and has enough sulfuric acid in it, and over 12.5 on the voltmeter. Can anyone help me?

 

It cranks over fine but it is just hard to start?
You have to crank it for 20 sec instead of the 10 that it used to take?

How long has it been doing this?

 

Just curious, how many miles on it?
Things that come to mind would be dirty/loose cables between the battery and starter, starter relay, a failing solenoid or a failing ignition switch.
Let us know hat you find on that.
As for taking longer to start, when was it last tuned including wires, what gas are you using and are you playing with the gas pedal?

 

I don't think it cranks right, because sometimes it'll just cutt out for a couple of seconds while I'm still hold the key in the start position. It cranks for about ten seconds. The vehicle has just over 60,000 miles on it. Its only been doing this for about a week now. I try not to use the gas when starting it, because I've heard that's bad for it, but sometimes it seems like it needs it. I've put premium in it everytime since I bought it.

 

When it just "cuts" out does everything go dead or only the starter?

 

Either the engine cranks, turns over, or it doesn't???
Never use the gas peddle, you will just be screwing up the ECU and what it does best.
As Spike has asked, does everything shut down or just the starter?

 

Just the starter cuts out

 

Then it is time to start checking some of the list I sent you plus anything else that may apply.

 

Ok if just the starter is cutting out then you need to look into the battery cables and where they attach to the starter.
I know on DI's the starter gets "hot spots" on them and if ti happens to hit one of them it will not work, bump it a few times to get past that spot and it works fine.
I do not know if this happens to DII starters or not.