1>BACKGROUND INFO: My automatic trans. 1995 318i just had a new Air flow meter installed. I always use 93 octane when I fill my tank. All my fluids and Air filters are all recently serviced. It has around 140,000 miles now.
2>MY SUSPISCIONS: I've noticed that when I stop at traffic llights and my foot is on the brake (as normal). The RPM lever sometimes jump wildly up and down between 2 and 3 and the car vibrates as if my foot is on the gas and the car is in neutral. Almost as if the car is revving up by itself.
3> DETAILS OF INCIDENT: Today after about 30 minutes of normal driving with no problems, I stopped at a red light and 20 seconds after the car stopped, the RPMs revved up by itself (between 2 and 3) then it dropped to 0 and the engine cut off and the car started to roll backwards (I was on a hill) when I tried to press the gas to go forward. I restarted the car like 5 or 6 times ( in the space of 3 minutes) to get the engine to turn over and the car to move. Each time the car would start but the RPMs stayed at 0 and then the engine would go silent. The only way I got the car to start again was by mashing the gas to rev up the RPMs in order to keep the engine alive...so to speak! Since then (3pm today)I had my car parked here in the city and have not returned to it as yet. So I'm not even sure it will start tonight when I go home.
I had a similar experience with my married daughters 1990 325i and it was the idle air control malfunctioning. I pulled the control, cleaned the electrical connectors with contact cleaner and then sprayed throtle body cleaner in all of the cavities and now all is well.
Could be idle control valve, could be a bad vaccum leak also, could be dirty fuel injectors. So here what you do first, spray the degreaser/cleaning stuff into the idle control valve, put some injector cleaner through (can't remember the brand name... something like 40k or 401k or something like that.. any one know the one I am talking about? comes in a can you pour in the fuel tank, or in a direct injection canister thing?) That should take care of it. If not you might need to take the idle control valve out and clean very well, replace O2 sensor, Mass air flow sensor, or vaccum leak could all be other possiblilities.
The other question is are you sure that they replaced the fuel filter correctly and the air flow meter? If that was just replaced and this thing just started, I would double check the installation. Or did this happen a bit afterward?
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