I am not sure if your car has both a Throttle Position Sensor (TPS) AND an Electronic Throttle Module (ETM) but the ETM has a sordid history of failures and I'm pretty sure there was a TSB about them that assured you could get a new one. I think that may have expired for your car though (10 years). You should check into that.
If you do some research on this site and others for "ETM" you'll find this is discussed quite a bit, and also that there is a Canadian company that has a (somewhat pricey) lifetime/forever fix.
IF that is indeed your problem. First you need to find out if it is a TPS or ETM that is giving you trouble. Again, I'm not sure if your car has one or the other or both or what. I suspect if it has the ETM it would not need a TPS.
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1998 V70 AWD->FWD Turbo 200k+
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