Rpm goes up down - 1995 Volvo 850

Maybe a contaminated throttle body.

This sounds normal to me. Why do you think there is a problem? If the RPM's are going up and down during acceleration, then I would say there is some sort of slippage. Have the transmission looked at for signs of trouble. Also, check the transmission fluid level for the correct amount. If it is low, find out why it is leaking. Gasket leak?

1st your car should not idle below 110 rpm even in gear

idle problems on these are caused by both broken or open vac ports or a dirty throttle body the A/F ratio cant get a correct reading

All the above is normal , except 2000rpm is a little high at idle . can be adjusted down to 1500rpm. the computer adjusts the engine speed . in drive the transmission loads up the engine idle drops to 1000rpm . in park engine unloaded rpm increase all normal.

it just needs a fuel mixture adjustment.

that should not effect the driving of the car,it's do to the loss of connection in the gear shifter.

try to reset the computer if that doesnt work reset the idle speed it may have picked up bad codes

It might have a bad Idle speed control motor.

I think the relay of the Blower Fan is faulty. Check it for bad sectors.

Check the vacuum hoses, but sounds like the IAC or even the o2 sensors. The computer will pick up on the o2 sensors but not the IAC..Go to your local ADVANCE store and they will check on computer for free :)