I have scoured over countless threads all over the net before starting this one and have not seen anyone post the results of cleaning grounds.

I did clean the firewall and transmission mount and added a ground from the frame on both side of the engine to valve cover.

While it did help a bit (doesn't shake like crazy anymore) I feel like there's still a problem somewhere.

Maybe a failing coil or something? Just got this car and wires look like recently changed. Starts up great. I see this ground running from the passenger side hoist point up into the fender.... Looking for some insight.

Thanks in advance.

 

Could be a failing IAC, among other things:

https://mazda626.net/topic/30382-iac...comment-257594