View Full Version : Losing power and a clattering noise from engine bay


06SilverG85
05-24-2009, 05:39 PM
First off, I have searched and searched trying to find problems similar to mine and I'm still scratching my head. Car is an 06 SS/SC with 80k miles.


First off, the engine started losing power under hard acceleration above 3500 rpms. This would cause the engine to start to buck. I naturally brought it back to idle and it idled very rough and varied between 1200 and 500rpms. I think got a CEL and went into reduced engine power. I wasn't able to get the engine codes at that point. Clearing the CEL and reduced engine power, the car is entirely driveable below 3000 rpms with very slight throttle application.

Now the other day I was able to get my Tech 2 and monitor the car. Of course now the engine didn't act the same. I revved it up past 4000 and felt the immediate power loss, but I also started to hear a sharp clattering sound as well as a weird sound out of the intake as if the supercharger was laboring to go faster. I let off as soon as I heard the loud clattering and the engine died. I got codes P0068 Throttle Body Airflow Performance and P0101 Mass Air Flow Sensor. I cleared the codes and was driving on the highway when it started to lose power entirely and blow smoke out the exhaust. After clearing the codes, the car was again driveable with part throttle. I did notice while babying the car around, my coolant temperatures are elevated. Running 180 while moving, but it quickly jumps to 200 whenever I stop (faster than it normally rises).

I really have no idea whats going on with it. I cleaned the MAP, SCIP, TB, and MAF and reinstalled them. Monitoring them with the Tech 2, none are throwing out crazy readings. Testing the car in the driveway after cleaning those sensors, it does the same clattering noise and loss of power, except now I can't get any CELs. I can gingerly give it throttle and it will rise up to 5500rpm before it starts to die and the rpms come down even with the same throttle applied.

All help is really appreciated. This is the first time I've ever had problems with the car and its really shaking my confidence in it. That clattering noise is scaring me, I am hoping it isn't anything terminal as its not repeatable at the same RPM. I'm wondering about the throttle body, the boost bypass valve or even maybe the supercharger clutches...

tru2nrtt777
05-24-2009, 06:21 PM
What color was the smoke?
White is lean
blue is oil
black/dark grey/brown is rich

Have you removed your spark plugs? What do they say?(Seriously, they can tell you a shitload on how your engine is running. Here is a link to help if you have never heard of this before: http://www.dragstuff.com/techarticles/reading-spark-plugs.html )

06SilverG85
05-24-2009, 06:32 PM
It was white smoke. That is a great idea to pull the plugs, didn't even think of that. I'll go check them.

Gun5
05-24-2009, 06:43 PM
white smoke = head gasket usually

tru2nrtt777
05-24-2009, 08:55 PM
True, white smoke can mean your burning water which is hydrogen and oxygen still too much oxygen... technically running lean... Lol.

YelloEye
05-24-2009, 09:08 PM
Was the clattering from the top of the engine? If so your head probably isnt getting enough oil to the hydraulic lifters (think thats the right term) You didnt install a breather filter on your valve cover did you?

06SilverG85
05-24-2009, 09:19 PM
Checked the plugs, all look similar, which is a plus. Blackened overall with the electrodes white and slightly rusted. They definitely could use a change... any thoughts?

To add, the white smoke I saw was very quick and occurred right before the engine died. It isn't constantly smoking, it was just a quick burst.


Cylinder 1
http://i691.photobucket.com/albums/vv272/ctfiero/Cyl1.jpg

Cylinder 2
http://i691.photobucket.com/albums/vv272/ctfiero/Cyl2.jpg

Cylinder 3
http://i691.photobucket.com/albums/vv272/ctfiero/Cyl3.jpg

Cylinder 4
http://i691.photobucket.com/albums/vv272/ctfiero/Cyl4.jpg

ItalianJoe1
05-24-2009, 09:24 PM
compression test is next in line. You broke something.

tru2nrtt777
05-24-2009, 09:36 PM
Cylinder 3 seems to have a bit more soot than the others, I dont think it is a problem just a FYI. What kind of plugs are you using?

06SilverG85
05-24-2009, 09:39 PM
I'm a little embarassed to say those are stock plugs, so yeah, they're gonna get changed.

tru2nrtt777
05-24-2009, 09:41 PM
Haha, I am running stock plugs too but I do only have 31k on my 06.

YelloEye
05-24-2009, 11:32 PM
Also though of a couple more things: cracked piston, cracked ring, head gasket, or the timing chain may have skipped a gear. Get a compression test to be sure on the first 3, with your mileage they should be within 5lbs of each other I would think.

06SilverG85
06-18-2009, 10:44 AM
Turns out cat was melted and coming apart. Knocked it through and it runs great! The clattering noise was spark knock. I've never heard it before so I thought it was mechanical.

DaBuzzard
06-18-2009, 11:42 AM
Turns out cat was melted and coming apart. Knocked it through and it runs great! The clattering noise was spark knock. I've never heard it before so I thought it was mechanical.

lolz, glad you got it sorted :twothumbs

Yep, knock sounds like someone dumped ball bearings down your intake, hard to miss when you know what it is.

And while it may not start out as mechanical noise, it will turn mechanical if not fixed. Like holed pistons, shattered spark plugs, shattered ring lands......

Boost gauge must have been going off the scale, no?

06SilverG85
06-19-2009, 02:17 PM
Boost gauge must have been going off the scale, no?

Wow you are absolutely right. When it'd start coughing and lose power, I'd notice the boost gauge hit 20psi real quick before it died. I should've caught that as back pressure through the engine right away, live and learn.

On a side note, anybody know the threads on that 2-bolt connection after the cat? I don't like the look of the nuts on there, so I'd like to put something stainless on there while I still can.