Deville starting problems

I'm having more and more trouble starting my 1999 deville. I think it is about a 4.5 to 4.6 litre V8 and I have almost 130,000 miles on it. Last fall (2006) the engine was slow to turn over and a few other things would occasionally happen during starts - such as the gas cap lid or trunk would open or the CD player would eject the CD. I only checked the battery then but found it to to be A-1. In case it helps, I remember hearing a solenoid from low in the front centre of car clicking as I removed and replaced the positive cable.

This fall, the starting problems are back and they're worse than ever. Usually, when I turn the key on but not all the way to the start position, the battery reading on the dashboard would be about 9.8 volts and it takes me about three tries to get the engine to fire. If the battery reading is over about 10.2, I usually won't have any problem starting the car but lately the battery readings haven't been that high. Once the car fires up, the battery reading goes up immediately to between 13.8 to 14.2 volts and, most of the time, I can get the car started for the rest of the day within one or two tries.

The past few weeks, I've noticed that the headlights will come on sometimes when I turn the key on. I'm also having lots of trouble getting the engine to fire - especially first thing in the morning. I even bought one of those portable power packs to assist with the starts when I'm on the road and I've had to use it three or four times in the past three weeks or so.

I'm a real amateur at this stuff but I suspect there's a short somewhere in the ignition system and I'm hoping you can suggest a couple of likely places to start the search for when I take the car into the dealer next Monday. Many thanks and I'll be pleased to make a donation for advice received.