S40 won't start unless I press the accelerator a bit.Doing that it starts right up.When running it idles correctly & runs fine.No codes show up no check engine light.Can anyone offer what to check?
Dennis

Here's a recent thread.
May be similar symptoms?
http://www.brickboard.com/AWD/volvo/1566891/S40-V40/rough_idlelower_mpg.html
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"Differences of opinions should be tolerated, but not if they're too different' - Sharon Craig

You might want to try cleaning the throttle body. Giving it partial throttle will open the butterfly to allow more air during start up. Once the engine is running, the computers will compensate for the air flow and make it run normally.

Either that or the fuel pressure regulator is fubar and it is too rich during start up.

Throttle body is clean.Idle control valve seems ok.Idle is smooth can't detect a miss.Any other suggestions?
Thanks
Dennis

"Idle control valve seems ok"
Are you sure? I pulled mine this morning since daughter #1 has been complaining that the car sometimes stalls right after starting...then is fine on restart.

The IAC was pretty dirty. Soaked/cleaned it. We'll see if it's any better this week.
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"Differences of opinions should be tolerated, but not if they're too different" - Sharon Craig

This all started when you put new spark plugs in, what kind of plugs are you using? What was the gap?

Follow the fuel line to the pressure regulator and then check the vacuum lines for the regulator. If a vacuum line has gasoline in it, the regulator is toast.

Other than hard starting, the engine idles and runs normally?