2014 Mazda 5 AT, 88K miles, mostly short city drives all the time.
Recently, I noticed that the RPM is dropping to around 750 almost always when the gas pedal is not pressed.
The issue is not happening when I am driving with cruise control engaged, - the car goes normally.
But as soon as I drive without cruise control and release the pedal, the RPM goes down - even when I'm rolling downhill and not pressing the gas, which I find weird.
Usually, when I take off, AT switches to the second gear and after that, I release the gas pedal and keep rolling - the car goes on. Now, however, it seems to drop RPM and after that, it's switching back to 1st (it seems).
Feels like a drag, like brakes are stuck - however, the brakes are not overheating, car is going straight and not pulling to either side, no vibration when braking, no burning smell coming from the brakes. The rear brakes are almost worn out, though. Brake fluid is less than 1 year old, and I'm am almost sure there is no issue with brake lines, since the fluid level is normal.
The air filter is fresh new clean, MAF sensor is clean - I just checked and cleaned it, just in case.
I have an OBD2 sensor constantly hooked up to my cheap Chinese Android stereo, which makes it possible to monitor various parameters while driving.
The only thing I can see that is slightly off is the Long Term Fuel Trim (LTFT) is 7.5%, which suggests that the engine is running lean, which can indicate a possible vacuum leak. However, it's still within the normal range, so, I am not sure about this being the reason.
I recently changed the engine oil (DIY 1st time), however, I don't see any leaks and even if the oil filter is completely clogged, this would result in such condition, I think. The oil level is just fine, I don't smell anything burning.
Also, used the snake oil fuel cleaner liquid (techron) recently and went for a long highway trip just fine.
Hours of research suggest that the torque converter or transmission is having an issue - i.e., slipping and going out, however, I don't hear any noises from that department.
On top of that - no CEL, no codes, nothing!
The only indicator that came up today is the DSC light, which blinked a couple of times and then got stuck until I did a stop engine start engine - which makes me believe that I should change brakes and rotors because these were changed 4 years / 34K miles ago.
So, I'm thinking about replacing the brakes and servicing the calipers now. I am still not convinced that there's a vacuum leak, however, I'm going to double-check this.
Has anyone ever experienced a similar issue? The only topic that is slightly related that I could find is this.
Any ideas?
Recently, I noticed that the RPM is dropping to around 750 almost always when the gas pedal is not pressed.
The issue is not happening when I am driving with cruise control engaged, - the car goes normally.
But as soon as I drive without cruise control and release the pedal, the RPM goes down - even when I'm rolling downhill and not pressing the gas, which I find weird.
Usually, when I take off, AT switches to the second gear and after that, I release the gas pedal and keep rolling - the car goes on. Now, however, it seems to drop RPM and after that, it's switching back to 1st (it seems).
Feels like a drag, like brakes are stuck - however, the brakes are not overheating, car is going straight and not pulling to either side, no vibration when braking, no burning smell coming from the brakes. The rear brakes are almost worn out, though. Brake fluid is less than 1 year old, and I'm am almost sure there is no issue with brake lines, since the fluid level is normal.
The air filter is fresh new clean, MAF sensor is clean - I just checked and cleaned it, just in case.
I have an OBD2 sensor constantly hooked up to my cheap Chinese Android stereo, which makes it possible to monitor various parameters while driving.
The only thing I can see that is slightly off is the Long Term Fuel Trim (LTFT) is 7.5%, which suggests that the engine is running lean, which can indicate a possible vacuum leak. However, it's still within the normal range, so, I am not sure about this being the reason.
I recently changed the engine oil (DIY 1st time), however, I don't see any leaks and even if the oil filter is completely clogged, this would result in such condition, I think. The oil level is just fine, I don't smell anything burning.
Also, used the snake oil fuel cleaner liquid (techron) recently and went for a long highway trip just fine.
Hours of research suggest that the torque converter or transmission is having an issue - i.e., slipping and going out, however, I don't hear any noises from that department.
On top of that - no CEL, no codes, nothing!
The only indicator that came up today is the DSC light, which blinked a couple of times and then got stuck until I did a stop engine start engine - which makes me believe that I should change brakes and rotors because these were changed 4 years / 34K miles ago.
So, I'm thinking about replacing the brakes and servicing the calipers now. I am still not convinced that there's a vacuum leak, however, I'm going to double-check this.
Has anyone ever experienced a similar issue? The only topic that is slightly related that I could find is this.
Any ideas?
