Shaky on acceleration and poor gas mileage

I just bought a 95 Subaru Legacy L AWD Wagon with only 110k miles. I have been going through fixing things like the HVAC lights, replacing all the brakes, etc, but I've come across a couple issues that I can't diagnose. On acceleration only, the car shakes terribly, and at first I thought it might be the alignment or wheels out of balance, but I had those checked and it still continues. Then I thought it was the engine/transmission mounts, but I realized that I'm getting very low gas mileage (16.8 mpg) and I thought it must be something else.. Any thoughts?

I would clean the:

Mass Air Flow Sensor (With MAF Cleaner)
Throttle Body Plate (With Carb Cleaner)
Idle Air Control Valve (With Carb Cleaner)
Check Plugs and Plug Wires
Check Air Filter

I would start with these first and see if it helps clean it up

Originally Posted by Baddog

I would clean the:

Mass Air Flow Sensor (With MAF Cleaner)
Throttle Body Plate (With Carb Cleaner)
Idle Air Control Valve (With Carb Cleaner)
Check Plugs and Plug Wires
Check Air Filter

I would start with these first and see if it helps clean it up

Definitely do this because it can only help, but its the shaking that worries me. Under what circumstances does the car shake exactly?

I'll do some cleaning, but I really don't think that has anything to do with the shaking.. It shakes at any speed and only when accelerating, if I take my foot off the gas it immediately stops.

Could it be bad cv joints?

Originally Posted by suntzuo

Could it be bad cv joints?

It could be, because my cv joints were bad, and my car would shake like crazy randomly, as well as my gas mileage only being around 21 mpg which seemed a little low.

I do think that one of the CV's is bad, so I'll do some cleaning and checking and replace the CV and get back to let you know if that fixed it. Thanks for the input!

Automatic or manual? If it's a manual might need to have the clutch replaced.

I know in my moms old 99 Mazda 626 (PIECE OF SH!T) when the clutch was on its way out not only would it slip very slightly it would shudder no matter what gear you were in.

I noticed you are in Sherwood. If you need any help checking things out let me know.

Also I may have mis-read some of what you were saying. The engine isn't stalling/shaking? It's the car that is shaking?

Yay finally another west sider on the forums lol all the ptown people are east siders.

I have to agree with what everyone else has said. No one said wheel bearings though...jack you car up and shake the wheel side to side, you should have no play.

I have an automatic, and I am very familiar with the feeling of a slipping clutch, as I have replaced many in my day. I also had the wheel bearings checked out with the alignment, and it was fine. The shaking definitely seems to be coming from the drivetrain. Feels like its the engine mounts and/or the CV's.

Check the drive shaft. I have heard of them wearing out can causing a hard vibration

Please do keep us posted because i've got the same thing going on. And even worse mpg.....:-(

Originally Posted by Baddog

I would clean the:

Mass Air Flow Sensor (With MAF Cleaner)
Throttle Body Plate (With Carb Cleaner)
Idle Air Control Valve (With Carb Cleaner)
Check Plugs and Plug Wires
Check Air Filter

I would start with these first and see if it helps clean it up

.....lol

^agreed

Also, if you drive agressivly then 17mpg isn't unreasonable. I've always got about 19 in my Legacy.

Originally Posted by subikid90

Check the drive shaft. I have heard of them wearing out can causing a hard vibration

I missed this post. Agree with this as well. Not quite the driveshaft though. Check the u-joints on the driveshaft.

Originally Posted by broknindarkagain

I missed this post. Agree with this as well. Not quite the driveshaft though. Check the u-joints on the driveshaft.

Thats what I meant lol