Last night I was on my way home going about 60mph with the tst on 1/1, then the tach cuts off and comes back on. As soon as it came back up the check engine light came on. I was a mile from home so I continued to drive it but if I gave it a little gas the engine sounded bad like it was missing or somethin. When I pulled in the driveway and killed the truck I noticed it was puffing out grey smoke.

I checked the codes and it gave me:
p0341
p0336
p0647

I know the tst can cause it to throw the codes but I didn't think it would cause it to smoke?? I started the truck this morning to move it and from what I could tell it was idleing fine, I didn't drive it down the road though.
Could a bad Cam position sensor cause this??

 

white or greyish? could be bad valve/valve seat. is there a puff puff sound in exhaust?

 

I'm not too sure it was dark outside. I just drove it a mile down the rode and it ran ok no smoke.