Over the last several months, I have been trying to solve a rather elusive problems. 1993 960 wagon, 174,000 miles.

History:
Typically, I start the car, it idles fine for 30 seconds, then idles rough for 1 minute, and then smooths out. After this I'm good to go.

Two months ago, the problem got worse, where it would stumble on acceleration, and jerk & buck on the highway. The harder I pressed on the gas, the worse it got. Finally got home on the back road going 30mph. And ofcourse, when I got within a 1/4 mile of home the problem went away. Due to this incident I changed both knock sensors, ETC, TPS, plugs, fuel filter, cleaned the oil trap, set the air box flap to feed cold air, oil change, dis-assembled & cleaned IAC, cleaned connectors (AMM, TPS, IAC, CAM sensor and others)and no gas on the diaphragm side of the fuel pressure regulator. After this VISA experience the highway problems and the cold idle roughness was significantly reduced.

Today:
Here we go again a month later. This morning, air temp 50, turned the key and she started right up. 30 seconds of fine idles then turned rough. I actually had to press the gas to keep it from stalling. Oddly, a slight press of the gas made it worse. I had to keep pressing and releasing the pedal to keep her running. after 2 minutes the idle smoothed out and I was off.

I attempted to accelerate just to have her stumble. I desperately worked the pedal to get up to speed. As I drove things got a bit better. It seemed I had to accelerate hard to keep going, but once up to constant speed it started to act up again.

I took the turn of life, onto the freeway. I accelerated hard, after the initial stumble and hesitation we were off and us to 60mph. Once up near speed, she jerked and bucked. Might have been a backfire or severe missing. I again had to hit the gas to keep going. I entire trip was spent accelerating hard and then coasting. Ofcourse, buy the time I got to work(20 miles) everything was normal.

Bizzare:
This morning I realized that the last time this occurred is when the car wasn't driven in the past 36 or so hours. As was the case today, the car was parked on Friday and not driven until this Monday morning.

PLEASE, I NEED A PLACE TO START LOOKING...

Thanks