Have you tried rotating the tires from front to back to see if you can take the tires and wheels out of the equation?

Miss under load could be mass air flow sensor, MAP sensor, or partially working components that are getting weak under load, like coil, plug wires, spark plugs, etc.

So, how did it do in gear ,brakes, gas?
Late home, okay, dark, hood up, someone gas it, watch for arcs,,

You  might can in the dark, you can hear one, usually.
Rubber hose, watch fans and belts,hair, maybe..

Well it was still pretty hot today but I took a look at the car anyway. I looked at all the wires and they all look good. The engine idles great. I revved it to 3K + and it still sounds great. I put it in drive, put my foot on the brake and revved it and it was ok. I did the same in reverse an it was ok but it felt like it moved too much. I must admit I only changed the mounts that looked bad. I guess I will change that last mount and try again. I originally changed 3 of the 4 motor mounts.

Hopefully changing that last motor mount will take care of the problem. If not then I think I will order the distributor and change it. And since I have to take the plenum off again to do that I might remove the intake manifold to clean the carbon build up. The build up is not terrible but if it is only a few more nuts and bolts, might as well get er done.

Thanks Justin. I do not consider myself much of a mechanic. I take these tasks upon myself just because mechanic labor rates are getting ridiculous and I really just cannot afford to keep paying those rates especially when the problem is not resolved.

I have the motor mount so hopefully I will get a chance to replace it next weekend. I sure hope it cools off a little!!!

It is an 02 mitsubishi eclipse gt, 3.0 L V6 with auto tranny. In straight line when accelerating at around 2K rpm it starts to shake and like I said, it does this intermittently. More precisely it appears to run fine for a few minutes but will eventually miss or shake and then it will continue to do so under load.

I really doubt that last motor mount is causing the problem, but I have a new one, I'll change it.

I really am leaning toward the distributor being bad as apparently the distributor was changed once before and in speaking with mitsu dealer they indicated it is a possibility.

This car is actually rather difficult to work on because of the V6 configuration. I am driving my 92 Volvo 940 at the time, 4 cylinder, non-turbo, non-functioning ac with over 300K miles on it. But it will do 75 on the highway all day long. And it is much easier to work on.