2006 Pontiac Torrent - Cold Crank - Rough Idle

[jcyancey]

I have a 2006 Pontiac Torrent - 3.4L V6 - 112,000 miles - I am the original owner. I have had a number of issues with the car over the last few months but what I am experiencing now has me stumped (I am a novice car repair person.. trying to learn more and save money). Not sure if this is significant, but in 2011 I had what the dealership told me was a blown head gasket. I found the oil to be milky / peanut buttery. It was covered by the extended warranty and the dealership replaced the head gasket. As far as I could tell everything has been good until a few months ago.

When I crank the car after it has cooled off it idles very poorly. Most mornings I crank it, wait about two or three minutes for it to idle down at which point it sputters and the engine dies. On the second crank it seems to idle higher and with a few presses of the gas pedal or more time it quiets down and runs normally. If I do not wait for it "warm up" and begin driving it feels like it loses power - I press the gas pedal and nothing happens for short periods of time until it "warms up". If I just turn the car off after it has run for a while and crank it again everything runs normally. So it seems to only be an issue when the engine is cool.

I also noticed recently that the temp guage was getting higher than it normally does (never in the red, just higher than normal). I checked the coolant level and found it was about a half gallon low. I flushed the coolant and replaced the thermostat about a month ago so that half gallon has been lost in that time frame. After refilling I have not noticed a substantial loss in coolant again, but it has only been a day or two. There are no leaks that I can see - no coolant on the garage floor or under the car in the work parking lot. After my cracked head gasket experience I checked the oil and it appears to look normal.

When the car is first cranked the exhaust is white and noticeable. It also has a different smell to it.. almost like a sweet smell or like it is burning too rich - this could be my paranoia kicking in - this could be normal given the circumstances.. i have no idea?

During this time the check engine light has come on with the following codes (I tried clearing them and they returned):

P0133 - Oxygen Sensor Circuit Slow Response Bank 1 Sensor 1
P0171 - Bank 1 System Too Lean
P0300 - Random - Multiple Misfire Detected
P1133 - Heated Oxygen Sensor Insufficient Switching Sensor 1
P1134 - Heated Oxygen Sensor Transition Time Ratio Sensor 1
P0301 - Cylinder 1 Misfire Detected
All of these errors registered more than once.. a total of 14 errors.

Thinking it was air intake / emissions related I did the following:
Replaced the air filter
Cleaned the mass airflow sensor with a purposed spray from autoparts store
Removed and cleaned the throttle body (replaced the gasket)
Changed spark plugs and wires
Replaced upper and lower 02 sensors

After doing all this the problem persists - and sadly, that is extent of my expertise Any ideas or suggestions would be greatly appreciated.

 

[melsg5]

if you have lots of white smoke and a sweet smell it could be a bad head gasket or cracked head. These engines also have had issues with the lower intake manifold gasket but would have expected the dealer to have used the correct parts when they did the work in 2011. Try using a cooling system pressure tester to see if it holds when warm for 15 minutes, do not exceed the pressure on the cap.

 

[jcyancey]

Thanks for the response. It has taken me a week to find a coolant pressure testing kit to rent that would work for this car. I found it at Advance Auto Parts (Im in the metro Atlanta area) - it is a Powerbuilt Kit 70 22pc Coolant Pressure Test Kit. I used the #5 fitting.

Melsg5, I am not sure how to interpret your suggestion. When you say to perform the test when the car is warm.. can you elaborate on what you mean by "warm"?

The coolant reservoir cap says it goes up to 15 psi. After driving home from the auto parts store, I let the car cool for about 20 minutes (hoping not to spray myself with boiling coolant). I removed the reservoir cap - the coolant was still quite warm and had pressure on the lines. I installed the testing kit and pumped it to 15 psi. After waiting 15 minutes I lost 2 psi. I looked as best I could at all the coolant hoses. No coolant on the garage floor. I saw no obvious sign of a leak.

I let the pressure off the tester and left the pressure tester installed on the reservoir. I cranked the car and let it warm up to the point that the thermostat opened (i was getting heat from the heater). The car cranked with no issue. It didnt idle rough like it does in the morning. The tester read 11 psi. I turned the car off and waited another 15 minutes. I lost 2 psi.

Can the loss of pressure be explained by the natural cooling of the coolant? Or do I have a leak within the engine indicative of some damaged gasket?

How can I know for sure that I dont have a defective tester? It is, after all, a rental.. I have no history on it. Thanks in advance for all your help.

 

[melsg5]

You have white smoke, a smell, and lose pressure. If a hydrocarbon test of the coolant is negative then it sounds like the lower intake manifold gasket, which is a common problem.