98 V70 XC.
Okay this happened three times in the last week. The first time was with all the power on ( lights, fan ) in the rain. Today was with no lights or fan. It has happened after running the car for a while and then stopping. At a stop, electric power dims, the arrow on the dash indicating the gear selector is in lower gear lights, when starting to go the car has no power, it feels like it is starting in a high gear. Moving the gear selector down does nothing. I think the srs light came on. Stopped the car, shifter to neutral or park then reved the engine. At first it reved weak then reved normal as the electric power seemed to come up. I tried to get it to happen again by stopping and going with all the power on but it wouldn't cooperate.
Thanks
Rob

 

Sounds like the transmission is going into limp mode (start in third) but you should have the check engine light come on. What's the mileage on the transmission and have you ever changed the fluid?

 

Had similar problem previously in extreme cold, radiator cracked. Doubt it is same situation, but symptoms the same. Fixed radiator and all was well (although still cold).

 

Sounds to me like you have an alternator that is starting to go out. Low voltage on these cars will cause performance issues and random lights to come on. Basically the car can't think straight with low voltage.