[98Z]

I have the same truck and the same issue. I've always assumed that mine was because one of the ears for securing the distributor cap down is broken and I can't get a good seal around the cap. The one screw is stripped out. I've been wanting to replace the distributor, but money hasn't been flowing that great lately.

Also, my check engine light is on constantly. The code says that the catalytic convertor is not performing as it should. I guess it's getting clogged up since my truck is pushing 200K. I want to remove it, but the engine light would remain on.