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Discussion Starter · #1 ·
Ok Car is 09 G6 2.4L engine has about 256,000 km on it. In the past few weeks it started running rough and the gas mileage has been terrible. It would also at times just stall randomly, it could be will driving or coming to a stop. Accelaration was also very sluggish.

Mechanic initially didn't think it was Cat related. We exchanged the upstream O2 sensor as it was throwing code P0420. It also threw the code P0013, and P0014 once, so we also replaced the Cam shaft position selonoids, (just to be safe did both the exhaust and intake).

Now, we replaced the cat, (after taking it off the mechanic confirmed it was plugged), and exhaust manifold was also cracked.

The acceleration sluggish feeling still at times occurs, but not as bad, mileage has increased for approx 400 km per tank to about 500 km per tank. Now in the last three days it has stalled twice while driving, (both times the TC light lit up then approx 5 seconds later car shut down), the security system activated and car could not be restarted. Had it towed to mechanic, (this is the fourth time in the past 18 months, the security system activated and car had to be towed. Once to a chain repair place, they couldn't resolve, towed to independent, he replaced a solenoid next to transmission, towed to dealer after the chain place, dealer said as truck pulled up they dropped car turned key and car started with no codes so they had no idea. This last time towed to new mechanic, he had car for 1.5 days couldn't get it to start.

As I was walking to see him. I thought wonder if pulling the battery cable will reset it? Sure enough I did this can bam car started right up. Got car home this mornign started normally drove 5 km and again TC light came on car stalled and security wouldn't let it restart. Again pulled battery cable and three minutes later I was on my way.

It is also important to note that for the last 3 - 4 months while this has been ongoing issue the idle has dropped from approx 1,000 before the issues to now idle about 5 - 600 rpm.

TB was thorughly cleaned about 6 months ago took car about 3 days to relearn idle position. Considering having it redone.

Any ideas what I should look at next.
 

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Discussion Starter · #2 ·
Update

Well in the last week car has stalled one more time, (last night). Again pulled battery terminal and was good to go it has over the last few days, (it almost stalled one other time), the MIL hasn't come on but when it almost stalled it threw a P0105 code and last night it has now a P0106code. So I am leaning towards a MAF sensor now, BUT when connected to my scan tool the MAF and BARO readings match perfectly 28.6, then when car is started the MAF reading drops to 11.9. Which "should" indicate it is functioning properly.
 

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Discussion Starter · #3 ·
Update

Seeing no one has an answer, (seemingly), including my mechanic. I thought I would add another update. Last week I had to leave town for a few days, unexpectedly, friend went over to try to start car. Battery was flat lined, (didn't even click). I had left my GPS and a 400 watt power converter plugged in for 4 days. Apparently this was enough to kill battery, (battery had also needed a boost when it stalled on the road and the 4 ways were left on for about an hour.

It was a new battery spring of 2013, (Walmart crap). I haven't had access to my multimeter to check battery as yet.

So fast forward to this morning again during my commute, (about 50 miles), near the end car just stalled, and wouldn't restart, (same symptoms of anti theft not allowing start runs for 5 seconds then stalls). So again I pull battery positive cable for 2 minutes, replace cable car starts immediately and finishes commute, (about 10 miles).

So is it possible that this "low battery" is somehow, (even though the altenator is recharging system), triggering the anti theft system to kick in and disable the car? It always seems to occur as I get close to finishing the commute which is approx 1 hour some stop and go urban traffic.

I plan to replace this battery, if not today then tomorrow.

Look forward to any insight anyone can provide.
 

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Seeing no one has an answer, (seemingly), including my mechanic. I thought I would add another update. Last week I had to leave town for a few days, unexpectedly, friend went over to try to start car. Battery was flat lined, (didn't even click). I had left my GPS and a 400 watt power converter plugged in for 4 days. Apparently this was enough to kill battery, (battery had also needed a boost when it stalled on the road and the 4 ways were left on for about an hour.

It was a new battery spring of 2013, (Walmart crap). I haven't had access to my multimeter to check battery as yet.

So fast forward to this morning again during my commute, (about 50 miles), near the end car just stalled, and wouldn't restart, (same symptoms of anti theft not allowing start runs for 5 seconds then stalls). So again I pull battery positive cable for 2 minutes, replace cable car starts immediately and finishes commute, (about 10 miles).

So is it possible that this "low battery" is somehow, (even though the altenator is recharging system), triggering the anti theft system to kick in and disable the car? It always seems to occur as I get close to finishing the commute which is approx 1 hour some stop and go urban traffic.

I plan to replace this battery, if not today then tomorrow.

Look forward to any insight anyone can provide.
When you say security, are you seeing it flash the SECURITY message on the dash? Have you tried to do a relearn on it?

A bad battery can cause all kinds of problems. It's worth a try to see if that fixes it.

Doug

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Discussion Starter · #5 ·
When you say security, are you seeing it flash the SECURITY message on the dash? Have you tried to do a relearn on it?

A bad battery can cause all kinds of problems. It's worth a try to see if that fixes it.

Doug

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Occassionally the security icon flashes just as it stalls not everytime though. But it presents exact same syptoms as the couple of times the security system, has kicked in, (been to two different mechanics for that as well, with no answer).

The car once it has stalled acts EXACTLY as it does when the security system is activated. It will start but only run for 2 - 3 seconds then the fuel supply is cut off. The only difference now is that if I pull the positive terminal for 2 - 3 minutes, then reconnect the car will fire right up as if nothing has occurs.

I took the battery back to Walmart, and even without a reciept they exchanged it for a new one.

Now lastly, for the last two weeks or so the idle is set vey low, (700 - 775), according to the live feed from the OBD reader.
 

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Discussion Starter · #6 ·
Not battery

Well I can now rule out the battery. New battery was in yesterday afternoon. This morning got about 5 miles from home and same thing. Again pulled battery and 2 minutes later I was back on the road, for the other 48 miles, without issue.
 

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Well I can now rule out the battery. New battery was in yesterday afternoon. This morning got about 5 miles from home and same thing. Again pulled battery and 2 minutes later I was back on the road, for the other 48 miles, without issue.
Your issue seems like a bad connection. At this point, my instinct is to go thru the battery cables and trace them out looking for corroded connections. That includes pulling the plastic/rubber covers off the ends of the cables at the battery and inspecting the crimps on the terminals.

Doug

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Discussion Starter · #8 ·
Will do

Thanks will do when possible, today we are getting the end rain from Patricia, and I have no indoor space..lol The terminals at the battery itself seem solid and they are spotless, nothing penetrates the box that covers the battery.

Your issue seems like a bad connection. At this point, my instinct is to go thru the battery cables and trace them out looking for corroded connections. That includes pulling the plastic/rubber covers off the ends of the cables at the battery and inspecting the crimps on the terminals.

Doug

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Thanks for the post. I am having similar issues with my 09 G6, 2.4. 212k.
Did you ever figure this out?
 
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