2006 Chevrolet Cobalt Knocking

  • 2.2L
  • 4 CYL
  • FWD
  • 175,000 MILES
Good afternoon,

My cobalt is making some serious knocking sounds. When I turn the key the engine turns over and then bogs for a second before barely catching itself attempting to idle. When I press on the gas a knocking sound speeds up with the speed of the engine. I checked the pressure in each valve and got these results: (97 / 131 / 135 / 132)psi respectively.
A little more detail if it helps, while driving the day before yesterday I noticed that when I tried to speed up quickly it felt as though my clutch was slipping, or as though I was losing a little power from time to time. It gradually got worse, and yesterday on my way home from work I was losing power more and more quickly. It got so bad that I could barely keep my car above 65 on the highway.

Here are the codes that my car is putting out:

P0128 - Coolant temp below thermostat regulating temp
P0455 - EVAP Emission Control System Leak (Large)
P0442 - EVAP Emission Control System Leak (Small)
P0326 - Knock sensor 1 CKT Range Perf/Bank 1 or 1 senor
P0442 - EVAP Emission Control System Leak (Small)

Any and all time taken to review my issue, and/or respond is greatly appreciated. If you have any questions or concerns please feel free to let me know at any time, and I will respond the moment I get your message. Please, thank you, and have a great day y'all.


Phillip B.
U.S. Marine Corps
Tuesday, August 4th, 2015 AT 12:37 PM

1 Reply

  • 30,869 POSTS
The p0128 means you need a thermostat the p0455 and p0442 means you have a evap leak or a issue within your evap system. The the p0326 could be the knocking noise causing that code. The compression is low for that engine. Does the knocking sound like its coming from the bottom end?Also does it feel like the engine is missing?
Was this
Sunday, August 9th, 2015 AT 8:11 AM

Please login or register to post a reply.

Sponsored links