GTP wont start. Electrical problems...?

My 1999 gp doesnt want to start after it has been sitting for any real amount of time. It will barely even try at first, then it will sluggishly start after trying for a while. It then idles very low and will shut off if i dont hit the gas to get the rpms up. After that it runs PERFECTLY i drove 300 miles no problem after it started (only because i had to leave then in order to get to college). It will then be able to start on its own (after idleing low for a second) but only for 15-20 minuets after it has been driven. The remote unlock doesnt work after it has been sitting and the horn is very quiet, which is why i think its all related to an electrical problem and not to the starter, etc. Ive never heard of this happening because of an alternator (it seems like once that has a problem its all over until it gets replaced) so mabe i just need to get a new battery??? What do you guys think?

If you have an Autozone or similar around get the battery and alternator/charging system checked. The diagnosis is free.

Also, check the battery cables and terminals for tightness and possible corrosion.

Welcome to AF.

im sure theres some place like that in the twin cities... hopefully its close enough to campus...

how do i check for corrosion and tightness? Pictures would be helpful if possible... i just wouldnt know where exactly to look or how to do so safely if that might be a concern

thanks a lot

At the battery you have the positive (red) and negative (black) cables. Just inspect them visually. Look for poor insulation, exposed wiring or poor contact. Next with a 8mm socket remove the terminal at each post of the battery. Inspect and see if there is any corrosion. Clean, if necessary.

If your radio Theftlock is active be sure to have your codes before disconnecting battery cables.

Remove the negative cable first so you don't accidentally short anything out by touching the wrench to something metal when removing the positive cable. To see if the Theftlock is active/enabled on the radio, look for the amber light near the word theftlock on the front of the radio to see if it's lit. If it is, you'll need the code or the radio will lock and be inoperative when you hook everything back up. If the amber light isn't lit, then you're fine.