my best friend's 1998 e36 318ti with 91,000 miles has a problem... when its running sometimes it doesnt idle, it just dies and sometimes its fine, when it doesnt idle it usually just goes away.... i would think its just the idle maybe but it also happens when we are driving... we were on the highway the first time it happened and he was stopped and when he went to pull away the car basically did nothing, the car didnt move, then RPMs went high and then the car finally started to move (the car is an automatic). today when we were driving we were outside the car talking (with it on) and out of no where the car just turned off.... and when we went back into the car minutes later the car had problems starting as it always does when this problem surfaces.... and when we were driving out of the parking lot the car started to almost bog down and then died, he started it again.... with problems... and then we were cruising down a street at like 35 and the car started to do it again.. and when he hit the gas to keep the car from dying the car had problems revving up and then we heard loud popping sounds..... sounded like backfiring and then it finally went... i dont know what the problem is... he bought it for $8000 about a month ago from a dealer... the dealer said it was the "idle" but dealers are dealers... anyone know whats wron with it

sounds like air flow meter the box after air filter

well would that explain the loud popping sounds and the random turn offs? and it has an after-market air intake that came with the car when we bought it

Before changing the air mass meter, look for air leaks, on the 318i there should be a pcv valve with a hose going to the rocker cover because of oil fumes, this hose gets soft and split which sucks unmetered air into the engine. the ecu will still inject the amount of fuel that is according to the air mass meter read out which causes the engine to back fire (lean out).
this only happens some times and not others because that split can sometimes close from suction and everything will be normal.
this hose is located on the back of the engine close to the inlet manifold there is 2 hoses joint together 1 is the pcv hose the other is a water hose BMW sells this complete. hope this helps

It could be the CRANK CASE VENT VALVE
http://www.realoem.com/bmw/showparts.do?model=CG73&mospid=47506&btnr=11_1562&hg=11&fg=15
it number 16 on the model. Mine was doing that for a while and I got it check out and that was the problem

Before changing the air mass meter, look for air leaks, on the 318i there should be a pcv valve with a hose going to the rocker cover because of oil fumes, this hose gets soft and split which sucks unmetered air into the engine. the ecu will still inject the amount of fuel that is according to the air mass meter read out which causes the engine to back fire (lean out).
this only happens some times and not others because that split can sometimes close from suction and everything will be normal.
this hose is located on the back of the engine close to the inlet manifold there is 2 hoses joint together 1 is the pcv hose the other is a water hose BMW sells this complete. hope this helps

Same symptoms on my car. The pcv valve fixed it.

mine did this and i replaced my mass air sensor and i was golden