2005 Saab 95, At cold start,1st start, car runs poorly, 2nd start car runs great

[craymorr2003]

I have a 2005 Saab 95 Aero 4 door, Automatic with 118K
During colder/cold weather, My saab 95 starts and turns over fine, but there is a problem with how it runs after the first start...
After running hot for a while, and shut down car, i'll get back in, restart and it runs smoother.

The 'problem" is kind of like a misfiring, most noticeable at 55+...poor performance, hesitation...
I have replaced DI Cassette, Air Filter (K&N), Fuel Filter, Fuel Check Valve, MAP Sensor, Mass Air Meter, Spark Plugs, etc.

Service Light Indicator: None, no codes
I notice these other symptoms: Supposed to be 18.5 gal capacity fuel tank, but when the fuel light is on and needle on E, or past E, I have yet to fill the tank where I ever put more than 15.5 gallons of fuel into that tank.
Saab repair facility here in Bedford OH were the one's to replace the fuel check valve, and said, shockingly" that the previous one had "disintegrated, it was gone, there was nothing there".
Another Saab facility identified a high knock count and wondered about the fact the turbo needle does not stay up, though still no error codes

Questions:
1. Might the fuel pump be starting to go bad, causing poor fuel delivery on first start/cold starts?
2. If the original fuel check valve had disintegrated, might pieces of it be floating in fuel lines/pump assembly interfering with fuel level readings, fuel pressure, possibly fouling injectors?

Quite honestly, I get 400 miles on average per tank before I have to fill up (but that's if I only have 15.5 gal tank), which is quite poor based on the mpg expected in manual. I always use quality 93 octane fuel and monitor tire pressure. No I have yet to see how far I can actually get on E.

So in summary, poor performance on highway after 1st start of day, cold starts...when I get back in car after shutting down, and start again it runs much better. So I generally let car warm up after first start, shut down and restart before I start driving. But man it's annoying. Any help would be appreciated.

****my 1997 900S has same engine with 287K miles on it and runs like it's brand new. I am honestly shocked how poorly the 2005 Saab 95 Aero runs in comparison. I know it's an apples and oranges thing, my 900S is standard and the Aero is Automatic, but just comparing engine performance, smoothness and acceleration, I am sure there is something wrong with the Aero, but none of these shops can help me with my theory until a error code is thrown *sigh*

[nordwulf]

The fuel light comes on when there is still 10 liters / 2.65 gallons in the tank (according to the WIS). So filling up with 15.5 gallons after the fuel light comes on is not unusual. I think the most I ever put in was 17 gallons and I thought I was running on fumes. It's good to have that safety margin.

I get about 26 - 27 mpg on average, 23 in town and 30+ mpg while cruising at 60 mph. So your mileage of 400 / 15.5 = 26 mpg is average and not bad at all.

Not sure about the rough running issue but perhaps could be some water in your fuel tank. A bottle of Heet is a cheap way to rule that out.

[craymorr2003]

Just curious, Does the Saab Display say you are getting 30 mpg? I've never gone above 26.1 on the display....

[nordwulf]

Yes, the Saab Display is actually quite accurate and 30 - 33 mpg is common when cruising at 60 mph.

Did you put in the Saab recommended spark plugs? These engine are quite picky regarding plugs as they also function as knock sensors.

[southsaab]

I second Wulf's suggestion on plugs. On mine I switched from 6ES to 7ES and the glitchiness went away. Don't have an Aero, but an Arc, just an Aero wanna be.

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[craymorr2003]

I second Wulf's suggestion on plugs. On mine I switched from 6ES to 7ES and the glitchiness went away. Don't have an Aero, but an Arc, just an Aero wanna be.

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I swear, 7 months ago I was on the thesaabsite and it said to use BCPR6ES11 now now only selling BCPR7ES11
i will give it a try

[nordwulf]

Recommended plug for the 2005 9-5 Aero 2.3T is NGK PFR6H-10 Laser Platinum.

http://saabworld.net/showthread.php?t=25916&p=67017&viewfull=1#post67017

[southsaab]

You are correct in that spec for plugs. I tried 7ES as an experiment to see if it helped with misfire at acceleration. And I gapped at .9mm (@.036in.), and it really helped. I do have a little more soot on the plug barrel, but the tip reads the same as the 6ES.

This may not help you at all, but I offer it as an " out of the box" suggestion. I can't fully explain it, but it works for me.

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