E30 Zone

Hello new to the forum> Recently purchased a touring 325i and it's running poorly. The garage did an exhaust hydrocarbon emissions test and found it not to be burning sufficient fuel. A normal car's emissions is 300, mine is 3000+?
The garage claim the car is running lean due to too much air being introduced into the engine. The fuel cannot burn with all this extra air. They thought it was a leak on the inlet manifold side, but could not find anything?
Anyone had a similar problem? Why is too much air being introduced?
Thanks
K

check all rubber inlet hoses, maybe its the air flow meter too, but first check the hoses

Wouldn't be something like a failed idle control valve being permanently open would it?

Cheers for the replies. Anyone any idea's on where to get a diagnostics test done to see if there are any fault codes in the ECU memory? BMW in Wolverhampton want Ԛ£106 which seems a bit steep? Anyone know of any independant BMW specialists in the west midlands?
Cheers
k