only when warm; rythmic fast/slow, fast/slow...
like a huge vacuum leak, but i cant find anything unattached.
cleaned the EGR valve, to no effect.

otherwise starts, and runs fine.
idles fine when cold.
any ideas?

 

Check PCV valve for sticking open and PCV hose for splits/leaks. Clean the Idle Air Control Valve, throttle body entrance, and backside of throttle plate w/ throttle body cleaner.

See DIY section for guidance and try search function for "clean iacv".

good luck

 

best take off the tb and give it a good clean with carb cleaner...

check around the inlet, have you an egr plate??? has the gasket on the inlet perished???

is the tb cable in good order, not sticking, and how is the spring on the tb

HTH

Noel

 

Cleaned the Fast Idle Thermal Valve (FITV) and tightened the ring inside the valve; idles fine now!
thank you!
this link was exceptionally helpful: http://www.cb7tuner.com/vbb/showthre...highlight=idle