2004 CTS 3.6 AT with just about every option. Best car ever, btw. Well, until recently.
I have 140k miles and 90k of them have been by me. The car has NEVER used a drop of oil, ever. I use Mobile 1 full synthetic and usually go 10k miles between changes. NEVER used any oil. Did I mention NEVER used any oil?
The car began to run bad and I found that if I bought gas at Exxon, it ran good. I suspected it was just a very sensitive system. Being that this car has always impressed me with the little things like automatically downshifting
when I am going down hill and am repeatedly using the brakes and the way the suspension stiffens while pushing it hard in the mountains, I guess I figured the new gas was just not good enough. Well, the problem did not go away
one day after using Exxon fuel. I took it to the dealer and they told me I had bad coil packs. Makes sense as those things could get weak over time and semi-bad gas would reveal it. I had them change the coil packs.
One week later, the Check Engine light came on. The code was for a bad O2 sensor. I figured it must have gone bad due to the continuous bad coil pack sending gobs of unburned gas down the exhaust. Maybe that's a stretch but
hey, funny things happen.
I opted to drive the car until I could get an appt at the dealer. My son drove it and informed me that the engine was making a terrible sound. Hard knock on the bottom end. Ouch! No oil. The oil had been changed just about the
time I had the coil packs done so probably only about 300 miles. Yes, I checked it after leaving the service center (I've had one experience with not filling the oil so I am a little paranoid and always check it when I get home).
I had a local shop order an engine from a wrecked car with 27k and he changed it. But, the very next day I could not start the car, key stuck, anti-theft thing. I gave the car a good charge (battery is only 2 months old and yes, it
is the genuine $200 dude). The problem remained. I disconnected the battery for several hours and when I re-connected it, was able to start the car but it ran strangely and shifts like it is in super sports mode. Next day, same
problem. I can get it to start by leaving the key in run and repeatedly unplugging the ECM until I hear systems begin to come on line (high pitch whine etc). Then I can start it but still the same issues.
I have read on here how these ECM's have a flaw which causes them to give all manner of symtoms. I'm assuming my ECM is bad and plan to replace it.
Now, could the ECM have caused problems with the firing rate of one side or the other or some other engine control causing an imballance in the crank case pressure and thus causing the use of oil? Why did it suddenly use up the
oil? There is no evedence of any leaks. Should I check the resistance of all of the sensors prior to changing the ECM? Am I missing something? By the way, I have completely elliminated the battery as the problem multiple ways.
It's not the battery.
I would appreciate any advice.
I have 140k miles and 90k of them have been by me. The car has NEVER used a drop of oil, ever. I use Mobile 1 full synthetic and usually go 10k miles between changes. NEVER used any oil. Did I mention NEVER used any oil?
The car began to run bad and I found that if I bought gas at Exxon, it ran good. I suspected it was just a very sensitive system. Being that this car has always impressed me with the little things like automatically downshifting
when I am going down hill and am repeatedly using the brakes and the way the suspension stiffens while pushing it hard in the mountains, I guess I figured the new gas was just not good enough. Well, the problem did not go away
one day after using Exxon fuel. I took it to the dealer and they told me I had bad coil packs. Makes sense as those things could get weak over time and semi-bad gas would reveal it. I had them change the coil packs.
One week later, the Check Engine light came on. The code was for a bad O2 sensor. I figured it must have gone bad due to the continuous bad coil pack sending gobs of unburned gas down the exhaust. Maybe that's a stretch but
hey, funny things happen.
I opted to drive the car until I could get an appt at the dealer. My son drove it and informed me that the engine was making a terrible sound. Hard knock on the bottom end. Ouch! No oil. The oil had been changed just about the
time I had the coil packs done so probably only about 300 miles. Yes, I checked it after leaving the service center (I've had one experience with not filling the oil so I am a little paranoid and always check it when I get home).
I had a local shop order an engine from a wrecked car with 27k and he changed it. But, the very next day I could not start the car, key stuck, anti-theft thing. I gave the car a good charge (battery is only 2 months old and yes, it
is the genuine $200 dude). The problem remained. I disconnected the battery for several hours and when I re-connected it, was able to start the car but it ran strangely and shifts like it is in super sports mode. Next day, same
problem. I can get it to start by leaving the key in run and repeatedly unplugging the ECM until I hear systems begin to come on line (high pitch whine etc). Then I can start it but still the same issues.
I have read on here how these ECM's have a flaw which causes them to give all manner of symtoms. I'm assuming my ECM is bad and plan to replace it.
Now, could the ECM have caused problems with the firing rate of one side or the other or some other engine control causing an imballance in the crank case pressure and thus causing the use of oil? Why did it suddenly use up the
oil? There is no evedence of any leaks. Should I check the resistance of all of the sensors prior to changing the ECM? Am I missing something? By the way, I have completely elliminated the battery as the problem multiple ways.
It's not the battery.
I would appreciate any advice.