Engine shaking after stopping

[LordBritish]

Unusual car noise after stopping

I've noticed this only twice.

After stopping, the car shakes for a few seconds and makes a funny sound. Then the shake goes away.

This is the sound it makes:
http://yourlisten.com/Yaya/unusual-car-noise

What could be causing this. The shake/noise happens after braking when the car is stopped.
Note, that this issue does not happen all the time. In fact it's hard to make it happen on demand.
The car doesn't really shake badly (or even at all), but the sound it makes is very noticeable and abnormal.

I'm a little concerned since it never did that before.

 

[Kalatrax]

Is it shaking because the RPM's drop down below 750? If that's the case I would suggest checking your air filter to make sure it's clean and then use MAF cleaner and spray down the MAF good. I do this every oil change. DO NOT USE CARB CLEANER.

 

[LordBritish]

I'll have to examine the RPMs next time it happens.

My air filter is clean, I cleaned it 2 months ago.

It's an S&B cone style filter (JLT CAI). I used a K&N cleaning kit and sprayed on that red oil.

I only noticed the shaking recently. Felt it only twice so far but I'm sure it'll happen again.

I'm afraid of something more serious like misfire or spark plug failure or worse.

Perhaps alternator?

BTW, I've never ever cleaned my MAF sensor.

 

[chaoscentral]

if you used too much oil on the filter it could be on the maf, so I'd probably start by cleaning that.

 

[LordBritish]

Any articles explaining how to clean the MAF ?

I'm guessing use Q-tip??

Ok, google told me

http://www.youtube.com/watch?v=P-TpCfbP1Xs

 

[G.T]

forget the filter and MAF for now.. remove your intake elbow and clean your throttlebody then reset KAM with a newer SCT or by unplugging the battery for 10 minutes

 

[Kalatrax]

Any articles explaining how to clean the MAF ?

I'm guessing use Q-tip??

Ok, google told me

http://www.youtube.com/watch?v=P-TpCfbP1Xs

That video is how I do it. The CRC MAF cleaner is $8 a can at an auto parts store.

 

[LordBritish]

OK, it happened again today.

I've already cleaned the MAF so that's not the problem.

Here is a list of things that are NOT the cause:

* Dirty MAF sensor. Cleaned it a few days ago.
* Dirty TB. Cleaned it recently.
* Dirty air filter. Cleaned it recently.
* Warped rotors. Car was making funny noise/shaking when the car was stopped so it's not the rotors.
* Bad motor mounts. Car would shake every time the car is at idle and that's not happening.

I haven't tried disconnecting the batteries but I doubt that will do anything. I can try uploading the tune again but I don't think it has anything to do with tunes or relearning. It has to be something else.

Here's a list of things that I've googled that could be a potential cause:

* Brake booster issue - but why doesn't the problem always happen?
* Torque Converter issue - could that cause my problem? Yes I have an automatic transmission.
* Automatic Transmission starting to fail? I had mine rebuilt once.
* Alternator failing? Replaced mine several times as you all have probably,

Anything else ??

Thanks.

P.S. I'll try to record the sound it makes and post it. It's a very distinctive abnormal sounds.

 

[LordBritish]

Ok, folks. I've made a recording of the sound now:

You can listen here:
http://yourlisten.com/Yaya/unusual-car-noise



In the audio clip you hear me accelerate then apply brakes and then you hear the unusual noise. I've completely stopped at that point.

I've amplified the anomalous noise part so you can hear it better.

It sounds like a bad diesel engine that hasn't been oiled in 30 years.

That happened without A/C on so it's not the AC compressor.

I did notice the RPM drop below 700 after applying brakes hard. Then the noise happens. Then the noise continues for a while as the RPMs increase to above 800 then the noise stops.

Any clues folks?

I need help.

 

[LordBritish]

At this time, I'm about 65% confident it's my torque converter dying on me.

Anyone else agree or disagree?

 

[BruceH]

Do you have an aftermarket cam?

 

[LordBritish]

Do you have an aftermarket cam?

Nope, stock cams.

In another forum, somebody mentioned it sounds like cam phasers going bad.

A little more info, when that noise happens, shifting into N does not make the sound go away imediately, that surprised me.

I did do a brake booster vacuum reserve test. You do that by shutting off the engine and pumping the brakes. You should be able to get 3-4 brake pedal pumps according to some website I read. I can only do 1 full pump and another partial pump. So perhaps I have a vacuum leak.

This is a weird problem for sure. Again, only happens under hard braking.

 

[Redfire281]

At this time, I'm about 65% confident it's my torque converter dying on me.

Anyone else agree or disagree?

I agree, if it happens when the car is in gear and in neutral. If you can't replicate the condition when the transmission is in neutral (freewheeling) then in all probability it is not the converter intermittently failing. IMHO, the only other cause would be a vacuum leak. Just my .02.