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  #1  
Old 5th December 2007
ajandmeg ajandmeg is offline
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Default Poor Gas Mileage

New guy-first post. I've always been into detailing my 1999 9-5 SE but after visiting this site I decided to do some up grades and preventive maintenance. I took off the air box and added a high flow intake, removed and cleaned my throttle body and installed a forge piston diverter value. All this made the car run a lot better, my mileage went from 18 mpg to 21 mpg. The problem started when I replace my oxygen sensors, installation went well and I purchased the Bosch sensors that do not require splicing, after one day my engine light came on and I'm now getting 8.1 mpg .
Any comments would be appreciated.
AJ
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  #2  
Old 5th December 2007
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SectorNine50 SectorNine50 is offline
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Quote:
Originally Posted by ajandmeg
New guy-first post. I've always been into detailing my 1999 9-5 SE but after visiting this site I decided to do some up grades and preventive maintenance. I took off the air box and added a high flow intake, removed and cleaned my throttle body and installed a forge piston diverter value. All this made the car run a lot better, my mileage went from 18 mpg to 21 mpg. The problem started when I replace my oxygen sensors, installation went well and I purchased the Bosch sensors that do not require splicing, after one day my engine light came on and I'm now getting 8.1 mpg .
Any comments would be appreciated.
AJ
Get the code pulled at an Autozone or similar and let us know what that code is, could help along the diagnosis process.

And make sure you actually get the code from 'em and not just the explanation.
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Old 5th December 2007
ajandmeg ajandmeg is offline
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Default

Sorry, I should have mentioned that a guy I work used his hand held and could not get any codes but he did get the check engine light to go off. Do oxygen sensors have that much control to make such a drastic drop in gas mileage, what else could have caused this-or are there too many to count?

AJ
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  #4  
Old 5th December 2007
Jssaab Jssaab is offline
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Yes O2 sensors are very important for Trionic. sounds like yo may have gotten a bad onw or th ewires got messed up when you did the change. Did o ukeep the old ones to swap back?
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Old 5th December 2007
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SectorNine50 SectorNine50 is offline
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Just out of curiosity, why did you change the 02 sensors?

For poor gas milage I'd check for boost leaks, change the spark plugs (Our cars take a very specific plug, look it up in the FAQ's section), and make sure the MAF is clean (instructions on this somewhere on the site as well, do a search).
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  #6  
Old 5th December 2007
ajandmeg ajandmeg is offline
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I just checked the wiring and it's all hooked uP correctly. To answer your question my car has close to 90K and I thought this was a preventive maintaiance thing you did near 100K. 8 mpg!!!

AJ
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Old 5th December 2007
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Quote:
Originally Posted by ajandmeg
I just checked the wiring and it's all hooked uP correctly. To answer your question my car has close to 90K and I thought this was a preventive maintaiance thing you did near 100K. 8 mpg!!!

AJ
Nope, 02 sensors aren't replaced unless needed. Are you sure those 02 sensors are compatible with this car? If you can, I'd try to put the old ones back in to see if it makes a difference. If not, I would check your plugs out.
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  #8  
Old 6th December 2007
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If they are not OE Saab sensors i'd wager these are the cause of your problem. Saabs are renowned for being very fussy about O2 sensors, try swapping the old ones back in and see if the problem goes away.
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  #9  
Old 11th December 2007
ajandmeg ajandmeg is offline
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Default Update

I like to first like to thank everybody who helped with this thread. I went to my SAAB mechanic and I got a code of 131 with low voltage- meaning a defective front O2 sensor. I called the company were I ordered them through and they sent me a new one-I have to send the defective one back to get reimbursed. When I got the new one in the mail I installed it and my gas milage is back up to 23 mpg.
What did I learn? Don't change your O2 sensors until you see a drop in gas milage and second, never ever throw your old parts away until the new parts have been on the car for awhile. I can laugh about it now but at the time I was really frustrated with the car and with myself-live and learn.
AJ
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