Why does my Volvo 850 surge in RPMs at startup?

Answer by  Amber40 (24961)

This could be caused be a few different things. First make sure there are no vacuum leak anywhere on the engine. Next check to make sure the idle air control valve is working like is should be. If it is dirty it should be cleaned along with another items on the intake that may have deposits built up on them.

Answer by  DRAZON (102)

It's normal. At start-up the fuel is leaned out so the engine has maximum efficiency. And the engine is less forgiving to changes in engine load. But, if it is real bad check for vacuum leaks, And maybe change the airfilter, If it does not change try using a higher octane of fuel.

Answer by  jimbob11 (195)

It's possible that you have a vacuum leak, and the vehicle's electronic control module is commanding the idle air control valve to close to compensate. Your idle air control valve may also be slow to respond and may need to be cleaned or replaced. You may simply need to reset your car's electronic control module.

Answer by  lawnmowerman (94)

usually surges due to unstable fuel pressure, have fuel pressure checked at a shop. also check battery , alternator load can do same thing.