OT - '91 Volvo problem

[ckmaggie]

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

[Don Plumley]

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

Good luck!

[gr8fl4porsche]

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

[Steve 82SC]

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