More 2000 RPM Stumble Problems

I posted last winter that I thought I had found the problem with the 2000 RPM engine stumble in the wiring connector to the Opti. A few weeks later the problem reoccurred and I had a good line on a new Opti so I replaced it. Now a few thousand K later I have the stumble back again. I tried cleaning the connector again but no luck. Has anyone ever found what it is that causes this because I have read on many boards that lots of people have this problem but no sure fire solution?

try cleaning the wires on your MAF, with alchohol and q tips. be very gentle though

Thanks Streamline. That was worth a try. The MAF sensor was pretty dirty. It was raining today so I cleaned it thoroughly and took it for a quick ride. It seemed OK up until I hit a small puddle, after which the Z got parked in my garage running on 7. Only thing I can think of now is ignition wires. They're stock replacement wires that I had installed about 4 years ago. Should have had a decent set installed but I was floored by how much the garage was charging me to do it and wanted to reduce costs. Bad idea I guess. I'll get a good set and do it myself with a new set of plugs as well. Hopefully that will be the answer.

I got the plugs and wires out. Found a surprising number of places that the plastic corregated covering used on the wires to held protect and separate them, was burned and/or melted to the plug wires. I see this covering used in the manuals as well. Is there a better cover that can be used? These wires have metal shields in places and it seems ludicrous to have a plastic covering on them near the exhaust manifolds. I'm wondering if they're better off with no covering at all.

Taylor makes sparkplug covers. You can get a set a Lordco or Best buy ~$45?