Vibration, loss of power, running rich in a Saab

[Brett Griebel]

I appreciate any help I can get on this matter. I am not doing the best financially at the moment and most advice I have received has been to throw parts at the matter to see what sticks. So I’d appreciate help narrowing the problem down. My mechanical knowledge is very very limited but I am trying (I have watched a whole host of Eric’s videos).

The Car:

2005 Saab 9-3 Arc 2.0T 5spd manual with 63k miles on it.

The Problem:

Vibration felt through gas pedal and floorboards with engine under load at higher speeds like on the highway. There also is a power loss with the car hardly accelerating when vibrating even with turbo boosting pretty heavy. The car also gets poor MPG, granted it isnt known for getting very good MPG to begin with but I tend to be very light footed and try to get the most out of the car and the last fillup was 22.5 mpg calculated based on miles driven since last fill up divided by gallons of gas put in. Also, when I go over dips and bumps on the highway I feel the vibration alter a little with the bumps, not sure what to make of that.

Things I have done so far:

I have changed my air filter, brand new OEM spark plugs. I have claned the MAF twice with MAF cleaner. I have cleaned the throttle body with carb/choke cleaner and I cleaned the MAP sensor with MAF cleaner. I rechecked my spark plugs a couple weeks after putting them in and found them to be black with a smell of gas. I checked the gap and it seemed ok. All my spark plugs were equally sooty, I was hoping there would be one standing out from the rest to help pinpoint things. I gave the coil packs a good eye exam and they all showed no sign of defect, granted I don’t know how effective that is. I have used the Torque app for my phone connected to OBDII reader. My car has NOT had a check engine light come on and no codes have popped or are in the system. I was monitoring the voltage from the upstream O2 sensor and it was showing at .7 on avg and when I would hit the gas on an on ramp in 4th or 5th gear I would notice it go in a flat line right to 1.0ish. This would just indicate to me that there is unburnt fuel making it’s way into the cat, am I right on that?

I have been recommended to change the coil packs in the car, the problem is they are not cheap. The cheapest I have found is 96 dollars a piece on rock auto and what is the likelihood of all 4 going out at once?

Thank you for taking the time to read this and I look forward to your tips/recommendations.

Topic

[college man]

start with a power balance test.do it both ways
spark and fuel.

[Jim]

I think you have a rich condition. check that upstream o2 and make sure it is toggling (switching from lean to rich). it should be around .02v to almost 1 volt moving very fast. try introducing a lean condition, like pulling off the brake booster hose. the o2 should go lean or around .02volts. if the o2 fails the above tests i would look into replacing it.

[Brett Griebel]

I was a little overwhelmed with doing tests so I ended up taking it to a saab specialist. It turns out (or at least it appears to turn out) that it has all been my fault. I have been trying to accelerate at too low of an rpm and when the turbo kicks in it makes it more so. My poor gas mileage is likely because of me trying to duplicate the symptoms when I am driving it and well I feel like a doof but thank you for the time you took to help me out with it.

[college man]

glad you got it worked out. 🙂

[Author]

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