80 450SL running rough?? New o2.

Actually, it will run nice and smooth for a while, then become rough. Also, when I punch it, tons of black smoke will come out!

I replaced the o2 sensor recently, and adjusted the fuel mix to run best before connecting the o2 wire. It ran much better, but have this intermittent roughness as mentioned above.

Can anyone point me in the right direction? .........BB

[ctaylor738]

Cold start valve or control,
warm-up compensator,
on/off ratio 'way off (likely if you messed with the mixture),
pressure damper diaphragm ruptured,
o-ring on fuel dist. shaft

Send me an email if you want the K-Jet troubleshooting guide - it's a 12 MB file.