my volvo s70 cranks good but will only run about 45mph and has no power

Get the codes read at the parts store. Write down the trouble code number and post it here. Someone will advise the most cost effective solution. There may be pending codes that have not lit the CEL yet.

If it's a turbo model, the turbo unit may have gone out. Depending on the failure, It may have gone into limp home mode, or it is not being detected by engine management and not giving a check engine light. There is also the possibility that the electronic throttle control is shot (1999 and newer). Irony is, I just bought a 1998 S70 GLT and have barely put 300 miles on it so far. Nice car though...

Bought a 2000 S70 that was a repo. Temp spare on the front right. The effect was front end out of level and this had thrown it into what I could only assume was "limp home" mode. Within a few hours spread over maybe 2-3 days I turned off the traction control switch on the dash (right) and it immediately started running like a champ. After changing to original wheel I was elated. Coolant would get low enough in the reservoir to activate light every few days but leak was not apparent. Three minor raises in temp, resulting in a blown head gasket and warped head. Trying to decide whether to scrap, part-out, fix. 230K+miles and it has a "PD" emblem on the back indicating police car. Thinking a week's work and $600-$800 in parts would probably be better spent elsewhere. Semi shopping for another with lower miles. At which point this one becomes the part car. Thoughts?