I just developed the dreaded low rpm stumble over the last couple of days. Between 1500-2000 rpm's at very light throttle the car will either miss or shudder. The shudder seems to happen at 1500 rpm while the misfire occurs right around 2000. Once you give it enough throttle to go over 2000 it runs great and pulls hard. Today I disconnected the egr vacuum line and plugged it, but the problem was still there. I hooked the egr back up tonight and took the car out for a cruise with my Auto X-Ray in capture mode. I got the problem to occur two times at approximately 1800 rpm (small shudder)and the only data that looked strange to me were the O2 readings: First capture: left o2 sensor- 110 mv, right o2 sensor- 39 mv. Second capture: left o2 sensor- 682 mv, right o2 sensor- 70 mv. Would this indicate a problem with my right O2 sensor/wire (seems like a very lean reading) or could it be indicatve of another underlying problem (plugs/wires or fuel pump)? I also ran the car at WOT after capturing these readings and experienced audible pinging. Prior to the last two days, the only times I experienced shuddering at low rpms were during a bad snow storm last winter and during a couple of severe rain storms this summer. The problem never persisted until now. Could it have been a bad O2 sensor wire acting up when wet that has now finally crapped out permanently? Any ideas would be welcome...Thanks in advance P.S. Optispark, ignition coil/module are new. Plugs have 14,000 mi on them (TR55's). TB and MAF cleaned last week.