Have your buddy disconnect the idle control unit, and plug the leads together. If the van will idle normally then, Viola! Its the stupid idle controller! If that makes no difference, try unpluggning the O2 sensor. The effect that the O2 sensor has on Idle, tho, is minimal. Most likely, something else was knocked adrift, while the exhaust work was being done. Maybe a vaccuum leak? Is the AFM connected, both electrically, and physically? A loose clamp on either end of the boot will lead to trouble...

________________________________
From: Jeff Lincoln <magikvw@GMAIL.COM>
To: vanagon@GERRY.VANAGON.COM
Sent: Mon, June 7, 2010 11:29:41 AM
Subject: 1.9L - Will not idle cold - when warm idles at 2800RPM

Hello -

I have a freinds who is having this issue. He said he has to keep giving the
bus gas to keep it running when cold. Once the engine warms the thing idles
at 2800rpms.

He said it has been running fine - the only change that was made is he
replaced the J-pipe int he exhaust system - said he used the same O2 sensor
that was in there.

Any ideas where he should start looking? TempII sensor? AFM? O2? Any of
these?

--
Thanks,

Jeff
'85 GL (Gertie)
'90 Carat (Grover - the noble parts donor)
'86 (We call this one Scrap)
'78 Bus (Melissa) Patty's Bus