’99 Escort wagon, 90K, reasonably well maintained here in the Nevada desert of Henderson, NV. We're just getting to our 100°+ summer days. I don't know if that's what's contributing to the following issue or not. The car feels as if it's stalling, then will resume for about nine or ten seconds, then will begin to feel like it's stalling again, repeat and repeat. The speedometer needle reading will flutter, then drop to zero while I'm traveling. The AC fan will get slightly weaker and weaker, while still blowing cold air, so the compressor appears to be working fine. The digital radio dial will get weaker and weaker until it goes dark, and the radio goes with it. If I shut off the AC during the bucking process, it doesn't seem to help anything, bucking-wise, nor power wise, although that test--where I turned off the AC--was done during the day, so I had no dashboard lights to compare between AC on or AC off. It just didn't seem to affect the overall problem at all when the AC and the circulation fan was shut off. I measured the battery voltage level--no load, engine off, and cold--and although it seems a bit low at 11.9V, it's still reasonably high enough to make me wonder if it's still hearty enough to not have the battery be an issue. I didn't check the voltage level when the car was running and the battery was under a heavier load. Is it just the summer heat that's worked its debilitating magic on the battery and now it's time to get a new one? Is it something else in the electrical system I'm not thinnin’ about that's the issue?