1994 Volvo 940 - idle and acceleration issues

There are two issues with my 940(automatic). They may or may not be related, but that is why I’m asking.

  1. When the engine is cold and at a stop sign the engine will rev up and down. After the engine warms up, the issue goes away.
  2. Also when the engine is cold, when taking off from a stop the car doesn’t seem to want to go. You can mash the gas all the was down and it just kind of slowly gains speed. Eventually (5-10 seconds) it will act like normal and go and shift fine.

I hope that is enough info and makes sense. I’m just trying to see what the problem could be and how to fix it.
Thanks in advance!

How old is this car and how many miles? If it is say 5 years or older, and has 80K miles or so, it wouldn’t be that unusual to have some gunk accumulate in the throttle body, particularly the idle air control. That’s the device the computer uses to control the idle speed. It might just need a cleaning. I’m always suspicious of air leak too, w/this symptom. But probably the best bet is to ask your mechanic if a cleaning of the IAC might be worthwhile.

The idle going up and down when the engine is cold is most likely a leaking intake manifold gasket. Change that and see if the other problem gets better as well.