Idles fine, stalls when RPM's drop too fast

[str99]

Hello everyone, I really need help with my car. I have an E36 1992 BMW 318ic with an M42 engine. Ever since I got it, the car randomly stalls out. It starts off pretty harshly, forcing me to start it while holding the gas pedal down. Once started and a few revs are given, it idles nicely and doesn't bob. Once I start driving, if the RPM's fall too fast, like if I switch to neutral from 3k RPM's or more, it would stall out once it got lower than 1k RPM's. It doesn't do it every time and to avoid the problem, I would stay in 4th gear until the RPM's got close to 1k, then only would I go into neutral without it stalling. It doesn't seem to be having all the much power either, all though the gas mileage is still good on it. I thought maybe because of the gas that I'm using, but that wasn't the case. Check engine light is not on, I cleaned the MAF sensor, throttle body, and changed spark plugs. I was thinking maybe the crankshaft or camshaft position sensor is faulty, but wouldn't the check engine light go on? Please help...

[spyderg0d]

Not always. I vote crank sensor.

[flyfishvt]

Poor performance with no check engine light says serious vacuum leak to me. Check the rubber intake elbow.

[m42b18]

Poor performance with no check engine light says serious vacuum leak to me. Check the rubber intake elbow.

This, I had a nearly identical problem in my M3. A tear in the intake boot will cause the exact symptoms you are experiencing so I would start there.

[str99]

This, I had a nearly identical problem in my M3. A tear in the intake boot will cause the exact symptoms you are experiencing so I would start there.

Awesome guys thank you for the responses. Checked the elbow, and the elbow is not cracked or show any signs of holes in it. I went from stock intake to a short ram intake, but the problem was there with the stock intake as well. I cleaned the camshaft sensor, no help there, just ordered a crankshaft sensor and will change it when the camshaft and crankshaft sensors come in.

[drivinfaster]

have you cleaned the idle control valve??



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[str99]

Sorry guys, I was out of town for a bit. I am wondering though, will changing camshaft and crankshaft position sensors even help? The check engine light is not on and never comes on. I used to have a check engine light for an oxygen sensor, but I cleaned that sensor and reset it and never had a problem since. What do you guys think?

[E36328Coupe]

No 1 answer

Poor performance with no check engine light says serious vacuum leak to me. Check the rubber intake elbow.

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And no 2 answer

have you cleaned the idle control valve??