Car start whell then start rough idle during warm up
 

Hi all , im new to the forum sorry for my english i type from Italy.
I have a v70 2.0 t 2001 whit a strange problem, when i start the car the first time in the morning the car run very whell but after 5 minutes when the car almost reach the operating temperature the idle get rough the car shake a bit and the dash pulse. The problem its only on idle. Then if i restart the car they run very whell il day long. any suggestion? Thanks in advance

is the "check engine light" on? Start by using an OBD2 scanner tool to check for any engine fault codes. A rough idle suggests a fuel mix issue, which can be measured by the OBD2 scanner. I would look for a few different problem areas 1) air intake and vacuum line leaks 2) dirty MAF or throttle body. Not sure if your year has an idle intake valve but if so, it may be dirty or not closing fully 3) temperature sensors - you can test the ohms of the engine coolant temperature sensor (under the upper radiator hose where it meets the engine) and see if there's a code for the intake air sensor or other sensors that send data to the computer. 4) check for any exhaust leaks. these leaks can throw off the front oxygen sensor which provides the lamba control (the fuel mix feedback loop for us ingegnere ) signal to the ECU.

the car don't nave an idle control valve all is managed by the etm. I found a broken PVC hose the one connected to the left side of the intake manifold maybe this vacuum leak is the problem ! I think unmeasured air can affect the idle. The strange things is the car start ever very well and begin ti shake during the end of the warm up and never stop . if i restart the car no problem untill a full night cool down