Cam gudies ??

[jondee86]

If you have stock cams and the cam timing has been changed with
the adjustable pulleys, it could affect the idle. Closing up the lobe
centres will increase valve overlap, possibly allowing exhaust blowback
(charge dilution) at idle.

If the cams have been changed to longer duration, the same problem
can occur. You may need to degree the cams to check the duration
and lobe centres. Aftermarket cams are usually marked on the end
of the camshaft, but you would need to pull the pulley off to check.

Cheers... jondee86