[Shaynecastonguay]

So when I stop the car and allow it to idle (or park it) the car's RPMs drop down, and the car usually recovers, then this continues in a cyclic manner until either the car cannot recover or I hit the gas. The car shows no problems while driving. 6 months ago, I was sent an evap code (P0455) ad traced it back to some destroyed evap lines around the throttle body and a stuck open purge solenoid. I replaced the lines and put in a used purge solenoid, I have not gotten a code since. I pulled the IAC valve a few days ago, cleaned it out with carb cleaner, tested it, it worked fine, put some PB blaster through it, and put it back in the car. The idles seem to have smoothed out (no more highs and lows) however when parked after some time driving, the car still will stall out randomly, with no warning signs. Thoughts?

 

[Flashheart]

Well, I often recommend a new CPS - simply in that it can go bad causing random stalling and/or hard starting - but will not throw a code. Beyond that if you were still having the idle issues I would say check for vacuum leaks....I usually have the car running - and start doing some bursts of starter fluid around the engine....in the rpms go up, you have an issue of some variety...like o-rings on injectors, or vacuum line....

 

[FC Saab]

Sounds like a bad purge valve. Unplug electrical connection to the valve and see if the surging stops. It will throw the CEL, but see if the rough run subsides.

 

[multisaabguy]

I would be checking all the vacuum lines, #1 cause of Idle issues, most issues actually.

 

[Shaynecastonguay]

well it appears that the rough idle HAS stopped by cleaning the IAC. The problem now is that the total stalling appears to be a separate issue. I have smoked the evap lines 3 times in this car because I bought it with 52k on it and all the evap lines were rotted. Would a bad purge solenoid completely cut out the engine without warning?

 

[Shaynecastonguay]

Also to note, sometimes when I put gas in the car, it will start up fine, and immediately drop back down and stall. This problem happens especially bad when I fill up totally.

 

[FC Saab]

The gas issue may be coincidental. Check all vacuum lines. Especially the one to the MAP sensor.

 

[jmkcc]

Vacuum lines are most likely culprit, but what about injectors? Anyone think they could be cause?

 

[Shaynecastonguay]

What do you mean about the gas issues? They could b unrelated? That would sure suck...

 

[Shaynecastonguay]

Update: went poking around the evap lines and noticed something odd right off the bat. There is a 1 inch (or so) grommet and a 3/4 line running into the engine right on top underneath the cover. This line has a connector right behind the "Direct Ignition" red plate on the engine. The connector appears to have two pegs, one for the 3/4 line and a smaller one that opens to nothing and pumps out air while the engine is running. What is this second port for? Does the 3/4 line completely cover both ports, or is there a line that I'm missing?

 

[Shaynecastonguay]

Ahha! Found a picture online that looks like it has a 3/16 line or so heading from that grommet to a one way valve then onto the throttle body, sound about right anyone?

 

[jakejm79]

Yes that is part of the PCV system, http://www.saabwiki.info/index.php?title=NG_900/9-3_Vacuum_Lines should explain where everything goes. I'd make sure all of those lines are in good shape.

 

[Shaynecastonguay]

Awesome, thank you. Hopefully this is responsible for my problems... no clue where that line ended up.