Rpm driving at 100klm rpm stays at 3000 if i press the gas a little rpm drops to 2000 but will incress to 3000 turns

The idle air control solenoid is very common to quit working. The only other thing would be a large vacuum leak.

I have a 2000 Chevy Tahoe that did the same thing. I changed the oil pump, new oil, and head gasket. It now has power and doesn't fall on its face when I step into the throttle hard. Hope this helps.

Yeah, the Volvo dealer that you are dealing with is the proverbial POS - if possible cancel the deal, get your dinero back and get the car from an outfit that can properly service the vehicle.

You have a mechanical bind. Disconnect the main linkage and work it all by hand. Everything should be free and slopy. Aerosol carb cleaner will help, but only when the engine is not running.

almost sounds like the cruise control is engaging

any smoke coming out the tail pipe? is it black, carbon smoke? if so your catalatic converter is clogged. replace it.

Maybe a short to the TPS or something shorting it out. There's also the IAC that really controls the idle but usually it will cause the RPM's to go up and down a little erratic if bad. The MAF sensor can cause major problems as well but since you already swapped the TPS and it helped and then stopped I would focus on that sensor and especially it's wiring to and from the ECM. Be careful with the sensor signal wire to the ECM can blow it if more than 5v passes or spikes.

Seems like we need a tune up . Change the plugs wires, air filter fuel filter. Is the check engine light on. If so have the codes pulled on the car.

14 dollar speed sensor , i just did mine

it sounds like you have a stuck IAC, Idle Air Control Valve. It meters air in when the throttle plate is colosed (foot off gas).

Autozone can scan for fault codes for free.

May just need cleaning. Try that first.

Idle Air Control (IAC) Valve —2.0L SPI Removal

1. Disconnect the idle air control (IAC) valve electrical connector (air cleaner outlet tube removed for clarity).

1. Remove the IAC valve.

1. Remove and discard the IAC valve gasket.