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Cobalt
A few questions. What is normal idle for a Cobalt? I have a 2007 with the 2.2 engine. It used to idle just below 2000 at 60 on the highway. Now it idles just above 2000 on the highway. Is this normal? Its got 158K on the odometer. Ive noticed it seems to be burning more oil and the fuel mileage has gotten worse.
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I have a 2008 and I'll look when I'm running on level interstate at 60 next time.
But I'm guessing you're seeing the difference between the torque convert clutch being locked up and not locked up. If you are on level road don't change your accelerator pedal with car going at that speed. Lightly touch the brake pedal just enough it would turn the brake lights on--that should unlock the torque converter clutch to give the engine slightly more revolutions for a little more power and quicker reaction to acceleration, as well as to be ready to downshift if necessary to 3rd gear.
I'll bet your car does not increase rpm's when you do that. Then you should see the rpm's decrease slightly and smoothly when you take your foot off the brake and especially if you let up slightly on the accelerator but keep it down to keep the engine pulling the car.
Is your engine warming up properly to 185 deg F according to the digital readout on the dash? Your thermostat may be opening too soon or may be leaking coolant past it and the engine isn't warming up fast enough. If you are in a very cold climate the engine may be operating normally trying to keep the engine warm and provide heat to the heater. See paragraph below.
Are you in a very cold climate where the transmission might be running colder. IIRC the transmission may not go into 4th gear as early when its oil is cold and the engine is not fully warmed up AND it may not engage the torque converter lockup in 3rd or in 4th under similar cold circumstances. I cannot be sure it does both of those, but I do believe it tries to keep the engine rpm's up some to get the engine warm and operating with less pollution...
2014 Malibu 2LT, 2015 Cruze 2LT,
If your thermostat is keeping the engine far below optimum temperature, your should get an engine light or a message in the dash screen telling you that the engine is running too cold.
If there's something wrong in the transmission that the torque converter is not locking up when the computer tells it to do so, I believe you will get a code and a check engine light. You didn't mention an engine light or a warning in the driver info center where the tire pressures and engine temp and average fuel economy all are displayed along with the oil life used. So I suspect everything is normal.
Kind of depends on your environment temperature wise and what you find after car is thoroughly warmed and you try to unlock and lock the torque converter clutch.
BTW, if the torque convert clutch doesn't lock up it makes a small difference in the fuel economy. Not a big deal in most cases.
AND I did understand that you meant idle at 2000 as in cruising along running at 2000 rpm. I mentioned the normal idle speed in park for other readers who might come across this dialogue.
2014 Malibu 2LT, 2015 Cruze 2LT,
However, if there's a slight incline up and the cruise control or the accelerator is pressed down, the torque converter allows the engine to speed up 300 or more rpms. Then it smoothly tapers down to 2100. So the torque converter is unlocking to allow more rpms and power temporarily in my car.
2014 Malibu 2LT, 2015 Cruze 2LT,
The codes that might eventually set with this one could be;
P0741 TCC stuck off
P1811 Max Adaptive, Long Shift (Need to use a scan tool and pull the adaptives to see if the system has to boost line pressure to apply one or more clutches/bands)
One thing to consider is if the engine is underperforming, that would have the driver open the throttle further to get to a given speed and that could cause the TCC to disengage.
I used my Autel scanner on my Cobalt and it has no codes. So I assume it is working right and this transmission doesn't unlock torque converter on brake apply.
I'll have to try my 14 Malibu and my son's 15 Cruze when I have it for service next time to see if they do react to brake pedal or just operate off inputs from the computer controlling them.
2014 Malibu 2LT, 2015 Cruze 2LT,
My guess is your car is doing fine at 60 mph. Mine has no codes.
I'd drive it an enjoy it. I like the 2.2 L engine over engines that have a turbo and are smaller. It just seems peppier to drive.
2014 Malibu 2LT, 2015 Cruze 2LT,