V6 auto throttle body, trans cable, idle

[VR38]

Long storey short, ended up changing the throttle body after removal for IAC clean, the one I fitted had the idle stop screw wound in too far so I adjusted it close to what the one was fitted, it idles ok at around 700rpm but is about 50rpm lower than the previous TB.
(the old TB had been butchered to some extent where the IAC fits).
I know it is within spec but it feels low at 700rpm, should I go thru the trouble of adjusting it or leave well alone?

Also, with respect to above, does the trans cable need any adjustment now I have changed TB?

After a run yesterday, and today pulling the TB to double check everything I noticed the back of the TB (inside, behind the throttle plate) there is already some soot built up, is tis normal?
I'm thinking I maybe due for a PCV valve replacement.

 

[Cheap6]

As it's already been messed with there's no harm in adjusting the TB stop. (If the cap was in place I would have said leave it alone.)

You shouldn't be able to adjust the TB stop so as to reduce the idle speed from the factory, ECM determined, setting. Perhaps there is something wrong with the MemCal, IAC valve (presumably replaced along with the TB though) or associated wiring, or the tachometer you are using isn't showing the true engine speed? You can adjust the TB stop so as to get the engine to idle too high though.

To set the throttle stop, with the engine at operating temp., block off the IAC valve port with a finger or thumb, and adjust the idle speed until the engine will just run (with all accessories, like cooling fan and vent fan off). That should be somewhere between 450 and 550 rpm. The idle speed should flare after you unblock the port. That's a simple test of the IAC valve operation.

Ideally the TV cable won't need any adjustment but it's a 2 second job to do so: release the TV cable by pushing in (then releasing) the metal button on the TB end of the cable, then open the TB until it hits the WOT stop, dragging the cable back through the ratchet to the correctly adjusted position.

Maybe PCV, maybe just engine wear.

 

[VR38]

ok, i adjusted the TV cable and there is no longer any slack in it.
Is this correct? (first time I have ever had to do it lol).
The cable was resistant then about 1/2 to 3/4 throttle it jumped the ratchet action into place.
Same thing happened 3 times i went thru the procedure.

 

[Cheap6]

Yep. That's what it is supposed to do.

 

[VR38]

Cheers.....