my 93 volvo 850 (automatic)when first driven for the day starts with no problem and idles fine but when put in drive and gets ready to shift into second gear it either cuts back and i have to floor it to keep going or it will shut completely off. if car shuts off it starts back up no problem, now once car has been driven for about 20 minutes or so, car runs fine can anyone tell me what causes this an d how to fix. thanx!

my car had a similar problem were it would stall after driving it for a short time when i would come to a stop or slow to go around a corner it ended up being a bad MAF sensor after checking and cleaning the throttle body and idle air control valve so maybe you should check the mass air flow

Check your idle air control pump. When the engine is cold, extra gasoline is fed to the cylinders and the idle air is supposed to pump more O2 to the vacuum tree to keep the idle at 950rpm.

I cleaned mine with carb cleaner, I soaked it and used an old tooth brush to get as much carbon black off as I could. Shaking it while submerged in cleaner helps also.
Inspect the vacuum tree for leaks while you are at it.

Klaus
--
Common sense trumps a PhD

I have the same problem with my '96/850 (manual transmission). Volvo dealer could not figure out what the problem was, and finally returned the car after being in the shop for months. Klaus - where is the idle air control pump located? How difficult a job is this?

Remove the cover from the throttle body pulley, the IAC is that round cylinder with a hose from the air cleaner coming in from the bottom and a hose going to the top of the vacuum tree. Easy to pull. I just loosen the hose clamps and when putting it back, use a pair of dykes to squeeze the clamps back on.

Klaus
--
Common sense trumps a PhD

Thanks! Worth a try. I'll take a look at it this weekend + report back ...

Bernie
'98-850/'07-V70

Thanks! Worth a try. I'll take a look at it this weekend + report back ...

Bernie
'98-850/'07-V70