Saab 97x 5.3i V8 slight rev RPM around 30mph-60mph

WickedHysteria

New Member
Hello, please help.

I'm the owner of Saab 97x 5.3i V8
MILES: 190,000

I've had an abundance of issues but the one I'm facing now is a slight rev [push] in the engine. Rpms slowly slightly jump when I accelerate around 30mph-60mph. It did it once a few days ago for 30mins then stopped. Now today after 35mins of driving it started again. I've read a few forums but I'm lost. Maybe TPS? I'm unsure. She does have a misfire. She also had issues with AWD where the wheels would lock up but turning stabilitrak off everytime I drive stops the issue. Next time with that problem is to just take AWD completely off the vehicle. But my issue now is this slight, real slight jump. I'll be going a consistent constant 40mph speed and she'll act like I pushed on the gas a bit more and accelerate just for a second and go back down. I want to make it apparent that it's a very slight and not too noticeable but its definatly there. And now that I'm sitting here with it theres a bit of an off smell but not strong. Anyone got any ideas? Thank you!
May 23rd, 2020.
 
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WickedHysteria

WickedHysteria

New Member
Hello, please help.

I'm the owner of Saab 97x 5.3i V8
MILES: 190,000

I've had an abundance of issues but the one I'm facing now is a slight rev [push] in the engine. Rpms slowly slightly jump when I accelerate around 30mph-60mph. It did it once a few days ago for 30mins then stopped. Now today after 35mins of driving it started again. I've read a few forums but I'm lost. Maybe TPS? I'm unsure. She does have a misfire. She also had issues with AWD where the wheels would lock up but turning stabilitrak off everytime I drive stops the issue. Next time with that problem is to just take AWD completely off the vehicle. But my issue now is this slight, real slight jump. I'll be going a consistent constant 40mph speed and she'll act like I pushed on the gas a bit more and accelerate just for a second and go back down. I want to make it apparent that it's a very slight and not too noticeable but its definatly there. And now that I'm sitting here with it theres a bit of an off smell but not strong. Anyone got any ideas? Thank you!
May 23rd, 2020.
Also she hasn't had trans fluid changed since I got her. But I've been told by many that with high mileage cars changing my fluid could make things worse so I'm uneasy. Shes had a recent oil change.
 

christo829

Well-Known Member
Changing the transmission fluid and filter should be done. It's the powered flushes that seem like they cause the most issues on higher mileage transmissions. Sounds like you have a bit more going on with that Saab, but that mileage means you're coming up on what should be it's *second* transmission fluid and filter change.

Are you saying that smell is coming from the transmission? If so, could be from worn out/burnt fluid. If not, we'd really need more details in order to figure out what it might be.

I'd try to solve the misfire as well, since that can cause unburnt fuel to clog up the catalytic converter, and depending on what's causing it, could cause rpm fluctuations, among other problems.

Start knocking out the basic maintenance issues and work up from there. How are the plugs/wires?
Did that oil change include the filter? Air filter changed recently? Checked for any pending codes? Pending or historic codes might tell you what the misfire or the surge might be, or at least point you towards an answer.

And the AWD should at least get serviced. Stabilitrac shouldn't lock up the driveline.

Good Luck!

Chris
 

Mooseman

Moderator
A slipping torque converter clutch could give a surging feel while cruising. And you should fix that misfire as it could also be part of the problem.

If a home flush or complete fluid replacement kills the transmission, it was likely on its way out and would have left you stranded when you least expected it. Sometimes old fluid will have friction material suspended that kinda helps the worn out clutches work for a little while longer. It's not the flush that kills it, it was already dying and delaying the inevitable.
 
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WickedHysteria

WickedHysteria

New Member
I had a couple of my guy friends look at it. Could possible be another coil damaged? Making the misfire worse? So I just bought 8 coil packs from rockauto.com. They'll be here Monday so I'll reply once they are replaced.
Yeah see I've heard all kinds of stuff about changing all the fluids in high milage cars. Exactly what you said- old metals that keep things together so when you put new fluid in it cleans everything... then bam, done for. *sigh* But then I hear some people say just do it- it won't cause harm so I don't know! Ah! I definatly can't afford a new one. I'd rather just fix this one because it has a great engine.
This car originally came from Ohio. Salty cold state. So all the rubber needs to be changed out due to salty roads corroding everything also.
Anyway I'm hoping it's just the misfire...
I'll look up and ask about the torque converter- thanks!
Any more advice from anyone is greatly appreciated.
 

christo829

Well-Known Member
How does the transmission fluid look and smell? If it's brown/watery/burnt, a fluid and filter change could make it behave better, but yes, it's still possible that materials suspended in the old fluid will help it maintain friction when needed. What often messes up high mileage transmissions is the pressurized backflush that some garages do. A pan drop drain and replacement of the filter is less intrusive. It doesn't replace *all* the old fluid, though.

And you got coil packs, but what about the plugs and wires? If they've never been changed, you can have excessive gap in the plugs from erosion, and possible arcing in chafed wires, both conditions that can lead to misfiring. Even if they have been changed, if you don't know when, you could also be coming up on another maintenance mark. If one of your friends has a scanner that can read misfires, that would help pinpoint the problem cylinder at least. Barring that, if they have an OBD-II module and an android phone, they can use Torque to read the real time data and see if you can narrow that down.

Cheers-

Chris
 

Mooseman

Moderator
Misfires can be caused by a number of things and should be diagnosed before throwing parts at it willy-nilly. They can be also caused by fuel problems, damaged wiring, bad compression, an air leak or stuck valve. Getting codes also helps in the diagnosis.
 

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