This winter, my 300SDL started very easily (1 crank after glow light) but once started it would run rough, and if I plant my foot on the gas pedal it would shake and smoke and -slowly- climb in RPM's. If I were to let off, occasionaly it would stall. This would be temps below 35 or 40F.

About 2 weeks ago I put in 6 brand new Bosch glow plugs thinking the old ones were getting weak.

Tonight it was about 40F, she started easily but there was still some roughness and she was hesitant to revv and was giving off some blue/grey smoke (not much), just like this winter.

I remember this being an indication of a stretched timing chain. As far as I know, the original chain has 270K miles on it.

My car will be in the shop for some front-end work, do you think I should get the chain done as well? He quoted me a price of ~$350 for the chain, is this a good price? It is just to roll in a new one, no guides or anything.

Thanks