I've got a 2004 Astra 1.6 SXi with the Z16XEP twinport engine.

Up til yesterday evening, no problems - since we replaced the EGR valve and we fitted a new cam-cover to replace the original, a couple of months ago. it ran ok yesterday when we came to move it in the garage. it wouldnt tick over if we held it steady at about 1600rpm the revs would go up and down between 1600 to 2500rpm there is a strong suction at the air-filter it revs freely from about 1700rpm upwards no misfire!

When the engine is allowed to go down to tickover it misfires and there is a strong suction at the airfilter and it burns oil as it stops when the engine stops there is a slight whistle as if there is air being allowed in to the engine??

We have connected a Solus to the vehicle and it doesnt show any faults just that it is in Limp Mode

Could it be the Fuel tank vent valve/inlet manifold valve??

Any ideas woul;d be appreciated