2019 Kia Stinger 2.0 base, 53,000 miles. Spark plugs changed at 36,000, normal oil change intervals, engine and cabin air filters regularly changed myself. I have noticed gradual increase in the following symptoms since June 13th, 2022. Rough engine idle, extra shaking and different rythmical noise to engine, sometimes increased clicking but not always. I have a slight downhill grade where i park and the car doesn't coast down smoothly on cold starts. Vibration, shaking even on newly paved smooth roads, feels like going over some bumps that aren't there. Overall feeling of sluggishness with normal driving as if the gas pedal does not smoothly engage the engine. Overall roughness and increased noise, some low volume humming/rubbing feeling while at steady speeds noticed at 45, 55, 65, 75 with louder volume occurring at higher speeds. Let off gas and vehicle slows does faster seeming to not coast as it previously did. Slight sluggishness uphill requiring increased pressing of pedal and engine not smooth. Downhill coasting does not increase speed, RPMs stay steady in a higher amount it seems. Doesn't want to downshift at times. I hear humming, sometimes growling in general. Braking seems more difficult almost fighting the engine to slow the RPMs.
I recently had a fuel induction service done with no change in these symptoms. I believe the symptoms are slowly worsening. No check engine light and no codes as per Kia. I drove it with a tech and they kept it and drove it themselves. They "did not find anything wrong." And they did not recommend that I "tamper" with the transmission stating fluid should be changed at 100k. (even though manual says otherwise... 60 0r 75k at extreme conditions meaning multiple short 5 mile or less rides, or 120k for normal long driving.)
Any ideas or recommendations? Should I just get a transmission drain and refill? This might be cheaper than paying $139 per hour diagnostic fees and $35 day car rental for another place to not find anything. I've searched for these symptoms and could be anything transmission related like the torque converter or solenoids.
I recently had a fuel induction service done with no change in these symptoms. I believe the symptoms are slowly worsening. No check engine light and no codes as per Kia. I drove it with a tech and they kept it and drove it themselves. They "did not find anything wrong." And they did not recommend that I "tamper" with the transmission stating fluid should be changed at 100k. (even though manual says otherwise... 60 0r 75k at extreme conditions meaning multiple short 5 mile or less rides, or 120k for normal long driving.)
Any ideas or recommendations? Should I just get a transmission drain and refill? This might be cheaper than paying $139 per hour diagnostic fees and $35 day car rental for another place to not find anything. I've searched for these symptoms and could be anything transmission related like the torque converter or solenoids.
