Thanks - you are right- I probably should sell it. I would like to see a MB fan and a DIY'er to buy it- replace the chains, etc and find out whatever is causing the rough cold idle/hot stalling.

to update, I was told by the mechanic that replaced my PS seal that noise was probably just the lifters too- so not to worry too much.

I asked him about the poor running engine when cold. He is a Volvo tech, and he admitted that he was not that familiar with Mercedes, but he suggested that it may be some sort of sensor that was thinking that the engine was hot, when it was cold and visa-versa. He listened around for vacuum leaks and did not hear any he said.

So, here are the updated details- some things have changed.
When it is cooler outside- when I first start it in the mornings- it runs smoothly, until I press the accelerator after it is running- then it will start to "stutter" and chug alittle. Like its misfiring. There were occasions when it did that, that it was putting out a gassy smelling smell out of the exhaust. I let it run for a bit and it clears out- then I take off. Then it will miss only for a second after it shifts into the next gear, when it goes to a lower RPM- then it clears out until it shifts to the next gear- then clears out after a second. Also- I have noticed- that when in gear- it idles smoothly after the engine warms up, but when in park or neutral, it misses (shakes). I have installed new plugs, but not plug wires. Could this possibly be the culprit? They look original, but still in good appearance condition, but I know that could mean little. However, I do not think that would cause the stalling the in the summer when the engine is hot.

Another thing- about the engine temperatures. When the temps are cooler, the temp gauge rarely goes above 85°C and when on the road- it goes down to about 60°. When it is hot outside- when in town - stop and go driving, the gauge goes to about 120°C, but when I get back on the highway or freeway, it goes back down to about 90°C. I think a thermostat may be in order? Also, I KNOW for a fact that the power auxillary fan is on the fritz. It has never worked and when I install a new fuse, it instantly pops, so something obviously not right. I tried disconnecting like someone suggested to see if it still blew a fuse, but I cannot get it disconnected.

I have already bought a newer truck, but still like to use the MB as a daily driver, which I am still doing. I just chug along until it warms up. I may still sell it yet to someone that has the time, money and know how to give it the attention it needs.

I am wondering if the thermostat, or a sensor of some sort may be causing some of the problems, rather than a vacuum leak? Whether I sell it or not, I would like to get it running smoothly again.

Thanks again!