OK, 
        Both axles with new boots replaced.

Took van out for a ride. 

After about 4 miles the lifters pumped up and the van ran quiet and strong.

O2 is disconnected and van is running good like that 
Connect and running issues return.

Now for the clunk question.

Ive notice for a few weeks that if I sit in the back of the 84 I will hear clunking as we drive down the road.

It is not the CV joints as I’ve replaced all. 

All seems fine under the van and it handles great.

It also shifts fine. 

So what are the usual suspects for rear of van clunking sounds? 

Shocks seem fine.  And the van is on a go westy lift with very nice springs.
Clunky thoughts?

Eric Caron 
84 Westfalia