The other day when I has driving my car at higher revs on the interstate maybe 3500-4500 rpms, my tach needle dropped quickly and my engine stumbled. It backfired a bit, but then seemed to correct itself quickly. I have no cats and 2 O2 downstream simms on my car. Any idea what gives? I haven't had it happen again, but then the otherday I went to start my car up and it stumbled and would die at idle. I turned around and went home. I disconnected the battery and ran my air to help the computer relearn the engine quickly. I haven't had a problem since. Do you think it's battery related? I think my battery is the original (1998). Any idea's? My voltage meter runs around 14-15 volts.