I just did this adjustment, and the first thing you need to do is remove the TB so you can really see what's going on.  Use a voltmeter set on ohms to check, and the TPS should switch immediate upon moving the throttle, and switch again only at max throttle.

Go Westy has their own version of a new TPS for $50, and a rebuilt TB with switch for $250. http://www.gowesty.com/ec_search_results.php?search_phrase=throttle+position You only need a TB if the shaft is so worn that it wobbles sideways. 

Stuart 

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Kevin Duvernay
Sent: Monday, January 12, 2015 9:59 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Hesitation off idle, throttle body issues?

Hey guys,

I recently messed with the tps adjustment to try to fix a 'bucking' with on/off throttle that I'm experiencing and it created a new issue. My 87 westy w/ 2.1 is now hesitant just off idle for a second or two. Depending on how the tps is adjusted, it can even actually stall. It's worse if I punch the throttle rather than ease into it. Once I get up off idle it runs fine.

Problem is, I cannot get it adjusted enough to be perfect. If fact, the adjustment seems to do very little to actually change the location where the switch switches on and off, which I believe is too far from the idle position (lever moves almost 1/4 inch before the switch clicks no matter how far I tighten the adjustment screw). If I tighten the adjustment screw all the way and tighten the set screw while still keeping the adjustment screw tight then I get it to run best, but not quite perfect. Very slight hesitation, but I know it's still there.

I fear there may be something worn in the throttle body preventing accurate adjustment of the switch. Also, the braided hose that the purple vacuum tube slips into seems a little damaged, may or may not be leaking slightly?
I taped it up, didnt seem to change anything.

Either way, the van ran perfectly before I tried to adjust the switch, FYI.

Time for a rebuilt throttle body? Anything else I can try first? Is it possible to rebuild a throttle body myself?

Thanks