OT - '91 Volvo problem
 

Parents came for turkey day visit. My father owns a '91 740 volvo. When warm, idle is dropping and almost stalling. If you accelerate quickly from a stop it stumbles but when you are very gentle on the pedal, it accelerates normally. At speed, car appears to run fine. When cold symptoms do not exist. Car is 4 cylinder fuel injected.

I am thinking vacuum leak. What is best way to check?

Any trouble shooting ideas appreciated. I can't find any info elsewhere and you guys are a great resource. And if I don't get this fixed soon, my parents may never leave....

Chris

I have no idea, but have found this a good resource for Volvo stuff: www.brickboard.com

Good luck!

I have been working on a '90 740 for a while now.

Brickboard is very helpful.

http://www.brickboard.com/FAQ/700-900/

Known problems with that model are

Fuel pressure regulator
RPM sensor
Dirty injectors and throttle body
Misadjusted or malfuctioning throttle position sensor
Fuel pump and filter
Fuel pump relay

On my Saab and a number of other Saab owners that I've spoken to, a problem such as you describe turned out to be the Idle Air Control (IAC) valve. It usually doesn't have to be replaced, just removed and cleaned with carb cleaner.

Steve