Gps Instability

[Fa310tx]

Hello...
I'm just wondering if this is a normal problem with the touch and/or alltel or if it's weird.
Currently, I'm using my own cooked rom, with google maps as my gps mapping. I open google maps and check to use gps. Some days it will lock 3-5 satellites within a minute or two, but most days it will simply time out with no satellites.
Here are a few examples...
I was in Florida a couple of weeks ago. When we got off the plane and got in the car, I had gps fix all way to the motel. For the next 5 days, I didn't get a single fix (not even in the same places that I had it the first night).
Monday morning, on my way to work, I was locked in the whole drive. Wednesday morning, on the same drive, not a single satellite.
Tuesday night, while laying in bed, I tried it and it showed me within 15' of my actual position, in my house (google maps satellite view). The next morning, on my couch, I had nothing.
Yesterday, I was riding around with some friends to get supper and no lock. Last night, driving home after supper, I watched myself moving on the phone.
It seems like I only get a lock 15-20% of the time. When I do, it's fast and accurate. That just seems a little odd to me.
JJ