My XC90 experience an extremely worrisome incident today that disappeared after I turned the vehicle off and let it sit for 5 minutes.
I was coming into Baltimore waiting at a red light after just exiting the highway, when I heard this eerie whine coming from inside the engine bay. It sounded much like the artificial emitter tone electric cars are now required to use when traveling at low speed.
Subsequently, I rolled the window down to confirm that this was my car - which it was. I know what a slipping belt sounds like and this wasn’t that. They tone was far more metallic. While stopped, I thought maybe transmission, so I ran the gear shifter through the drive settings which did nothing.
Next I put the truck in N and gave the throttle a blip - and this was the first big red flag; the engine revved, but didn’t settle - it dipped then went back UP! Around 2000rpm or so for about 2 seconds with my foot off the accelerator. I felt a few power pulses then it dropped. The whine pitch didn’t change throughout.
I repeated the problem - blip, foot off accelerator, RPMs wobble, rise and hang, then dropped. By now the light turned green. I slipped the car into Drive and gently pulled off. I was met by with a scary rattle from the engine, during roll off and load and lumpy, reduced power - almost like I lost a cylinder.
I immediately think I’ve killed the engine! I pulled over and checked the oil. Oil was a little low but well within limits. Full synth, 6000 miles on it and the filter, so, it’s due for a change in 1000-1500.
I checked the vehicle info screen - no warnings or messages. No warning triangle. Nothing.
I let the truck rest for about 5 minutes, started it back up and now everything appears to be fine but obviously I find this highly disconcerting. Anyone have any idea what just happened?