I have a 98 GT and I was on the freeway the other day when I noticed that my battery indicator came on, so I checked the battery gauge and it was off the high end. I got home and popped the hood and the battery had expanded so much that it blew it's top off. I replaced the alternator and bought a new battery thinking this would solve my problem and it did for a while, but now it seems that when i'm idle at a stop light the battery gauge drops below normal and when putting up or down both windows my lights dim, it gets worse when I turn on the a/c. However when I'm on the freeway and doing 70 or more the gauge tends to head towards the high end, not so much though. If anybody out there could help me out I would appreciate it. I've also read other threads and a lot of you mention ground wires and so forth, now being a noob is it better to take it somewhere to get checked or how simple of a process is it to check ground wires and where along the engine compartment are they located.