Replaced the OP sender last weekend due flaky indication at guage. She worked perfectly for the last 3 days and during the drive into work today the op guage started flaking out again. Guage spikes to max on accelleration (light or hard) and will sometimes drop down to zero (for a few seconds) in idle. No warning lights come on so I'm confident the OP is ok. Just wondering what else might be causing the problem. Bad ground or poor connection behind the cluster? It'* drives me nuts when the guage acts up.

Sounds like a bad wire connection. Start at the plug on the sender unit, look for loose connections, frayed wires, etc.

Check the connection at the switch and also look for any wires that might be resting against anything hot that could've melted the insulation off the wire