Got a free 84 245 that was destined for the junkyard. Body is solid. It needs work, but mostly deferred maintenance stuff like struts, water pump, bushings, etc.

One problem I can't figure out is, the car surges at idle. Surge might be the wrong word. The tach moves up/down between 500 and about 700-750 rpm once every second. Strangely, if it does this while I'm sitting at a traffic light in drive, the rear end of the car will move rhythmically up and down. Never seen anything like that before.

For the surging, I am thinking TPS or air mass meter. Leaning more toward the air mass meter because when you hit the gas, it stumbles for a couple seconds and acceleration off the line is choppy until the car gets up to about 25, then it suddenly wakes up and finds its balls.

But what is with the undulating rear end??