Quick diagnosis - sluggish '99 forester?

[backwoodsboy]

Ok boys and girls,

 

Ive never been a forester man per-se, but my cousins wife owns one, and is having some troubles.

 

It acts sluggish, and there is poor throttle response. (acts like cat. is partially plugged)

 

I suspect perhaps a MAF sensor?

 

Anybody else have this trouble?

 

-1999 Forester (runs at normal temp)

-108,000 miles

-A/T

-Does NOT have check engine light on.

-Air filter is CLEAN

-No cracks or leaks in either air box or in the intake.

[idosubaru]

any recent work done on it? mileage? has it ever had a tune up? it's due for a timing belt at 105,000 (though that shouldn't cause this), but wondering if that work was done. vacuum leak....?

[nipper]

I'ld do a tuneup, plugs, wires, filters, pcv valve, front O2 sensor ....

 

 

nipper

 

and yes its due for a timing belt.

 

 

nipper

[OB99W]

I'ld do a tuneup, plugs, wires, filters, pcv valve, front O2 sensor ....

Yes, if not done recently. Don't forget the fuel filter in particular. Also, if the fuel quality is poor, the ECU may sense knock and retard timing. Is it sluggish in general, or is there a road speed range or other circumstance under which it's especially poor?

[backwoodsboy]

There was a deer hit incident at about 60,000 miles, where the front end (incl. timing belt) was all re-done professionally. (1000.00 in engine work alone)

 

It idles nice, but the sluggishness is pretty constant, and if you feather the gas pedal, there are little "sweet spots" where it will surge for a second......then right back to slug-city.

 

There appear, and sound to be NO vacuum leaks.

 

I just dont wanna thow parts at it if I can help it .....just priced MAF sensors *OUCH*

 

Could it BE a bad knock sensor? We used to sell them by the dozen when I worked for Subaru!

[nipper]

No matter what, a tuneup is NOT throwing parts at the car, its a regular maint item. A smooth idle does not mean the car doesnt need a tuneup.

 

You need to do that first. Your O2 sensor is over 100,000 miles which is there expoected life. They live much longer then that, but failing at around 80K on up is not unusual.

 

After that you have a good baseline. Then we can look at other things.

 

Has anyone pulled the codes?

 

nipper

[backwoodsboy]

No codes pulled yet..... that is the next item of business.

 

Ive been so much an "old school" ea81 man lately (if "this" is the symptom, then "this" is your problem kindof thing) ...that I tend to think that way about new-gen stuff.

 

I have to dig out service records and see if it had a tune up back at 60K or not.

 

Is it Autozone that pulls codes for free I think?

[nipper]

Is it Autozone that pulls codes for free I think?

 

Yes

[idosubaru]

advanced auto parts and autozone both do it for free. the ones in rural areas, like where i live, just give you the scanner to do it yourself.

 

tune up. pay particular attention to the wires, are they Subaru OEM wires or some aftermarket brand? if they were replaced, but with aftermarkets, then i'd suspect those. these EJ engines are nothing like your EA series stuff, they are very sensitive to spark plug wires. i'll throw anything on an EA engine and they rarely have issues, throwing anything except Subaru or Magnecor on an EJ engine is risky. i've seen brand new aftermarkets cause problems. sensitive little jokers.

[backwoodsboy]

The wires appear to be original OE. I dont know what it has for plugs, though I would assume OE as well..... seeing as it was the Subaru stealership that did the engine work.

 

I appreciate the help and quick replies BTW!

[Gloyale]

any recent work done on it? mileage? has it ever had a tune up? it's due for a timing belt at 105,000 (though that shouldn't cause this), but wondering if that work was done. vacuum leak....?

 

 

A timing belt that has slipped just 1 or 2 teeth will definately cause poor power, throughout the operational range. However if it has "sweet spots" this is probably not the case, but removing the end covers and verifying that it is in time would be good to check.