Sometimes my '96 Legacy feels a little underpowered, like its laboring a bit, and it seems to be a little low on power.

 

But then other times, it feels really peppy, like it should.

 

I have noticed when it feels like it is laboring, the vacuum never goes about about 23mmhg when coasting.

 

When it feels peppy, the vacuum will go to like 28mmhg when coasting.

 

Also, when it feels like it is laboring, especially before the engine oil is at normal temp, pressing the throttle even slightly will drop the vacuum to almost zero.

 

Whereas, when it feels peppy, pressing the throttle under similar conditions the vacuum goes only to 10mmhg.

 

Any ideas on what this would be? Sometimes it will go several days in the 'laboring' mode, then suddenly change to the 'peppy' mode for a while, etc.

 

There is no CEL.

 

It has done this if I remember correctly since I got it pretty much, I just never really payed much attention to the vacuum when it did it until recently. The difference in feel isn't huge between peppy and laboring but it is definitely noticeable.

 

'96 Legacy Brighton 2.2L 130k miles auto trans.

Mine does the same thing. Seems to be most noticeable when going up hill. I never thought to hook up a vacuum gauge up and see what it does though.

 

My best guess is a stuck or sticky evap system solenoid. Not the purge solenoid but one of the ones at the back near the fuel tank. I've had a pretty constant CEL on with a P0106 code which I think is related, but I haven't cared enough to dig into it and fix it.

 

Yours could be similar. Try pinching off vacuum lines that lead to the Evap or EGR solenoids and see if the issue goes away.

Well lets start with basics, when has this last had a real tuneup and new PCV valve.

 

 

Tell me what the gauge reads at idle

 

http://www.classictruckshop.com/clubs/earlyburbs/projects/vac/uum.htm

 

 

Once the car is tuned we can go from there.

 

How old is the O2 sensor