Major Stalling problem! Help please!

[grk nickafis]

When the car is on the cold side but not Cold, if im just cruising and i put it in nuetral or press the clutch, the RPMs bounce from like as low as 300 bounces up to 1k and keeps doing that untill i pop it into gear. If i let it go long enough it just stalls. i cant press the gas or anything untill i pop it back into gear. if i roll to a stop (assuming it didnt stall), the rpms go back to a steady idle at about 1k. At a cold start (ONCE i did this, only once), i punched the gas from 1.5k rpms and its sputtered its way to 3. I'll try to get a video of this. I mean i have one ill try to post it.

[grk nickafis]

I also hear a knock wen i rev up and let it go. wen the RPMs are coming down, theres a knock. Not while its reving up tho or idling. idk if it has something to do with that.

[Zwicked]

Try properly setting the idle and testing the AAC to make sure it's working. Also test the coolant temp sensor and the connector for corrosion on both of these items. Also possibly a failed injector if it sputters and doesn't idle or run smoothly. The fact that it almost stalls and tries to recover could be one of these issues.

The "knock" could be your cam VTC springs are shot.

[grk nickafis]

I had a friend of mine look at it and said there is an obvious vacuum leak that could cause these problems behind my engine. Any Ideas of which vacuum line it could be or where i could find a chart of all the lines?

[labcoatmonkey]

I had a friend of mine look at it and said there is an obvious vacuum leak that could cause these problems behind my engine. Any Ideas of which vacuum line it could be or where i could find a chart of all the lines?

I have a similar problem but its not due to a vacuum leak. Pressurize your intake system with a compressor or see if a shop has a machine for that, and look for vacuum leaks by listening or a lit cigarette (so simple but briliant lol). Also check the main big main intake pipes and turbo pipes if you have any. Im just curious, would a bad temp sensor make the engine stall or bounce at idle from 100 rpm to 1000?

[grk nickafis]

well my temp sesor was replaced about 3k miles ago according to the receipt. I'll try the cig thing, i never thought of that haha. what would pressurizing the intake pipes do? I know the leak is behind the engine.