01 outback valve cover gasket failure :-\

Aside from the CEL codes concerning cam shaft, what you describe it does during driving is the same thing mine went through (2001 Outback 76k w/possible head leak), mine turned out to be a bad O2 sensor.

I guess what happened was it lost or threw bad data, and sent all sorts of stuff "downstream" out of whack including; misfires, hesitation while acceleration (almost like a tranny problem), raw gas dumped through cat, no accelleration when hot/moist/raining weather, and "surging" while coasting down hill (does it stop surging if you put it in neutral?).

It NEVER threw a code except after about six weeks of on and off problems. One day it would be fine, the next it would be terrible. I'd stop, and restart, and it would be fine, or not. Once the O2 sensor finally quit, then it coded bad O2.

A lot of the stuff you did probably needed to get done anyway due to the gaskets, but I am wondering if you should try a new O2 sensor before doing more complicated stuff.

Thanks for your reply. I think I stumbled upon a very similar story to yours at the nasioc forum, and informed my mechanic (who is far from dedicated to Subes unfortunately) the "might try an O2 sensor if all else fails--seems it cleared up a really puzzling case with similar symptoms" and he acknowledged having seem a similar story somewhere.

In my case, there seems to be an ambient temperature dependency like yours (hotter=bad), but opposite your experience with moisture. For instance, recently, it rained and cooled things down to around 70F. While raining and cooler, the car ran with no problems. Hot and dry seems to be problematic.

But at any rate, if this wiring harness replacement doesn't fix it, swapping 02 sensors sounds like the next cartridge to put in the ole shotgun. I agree that the rebuilding of the heads and getting an aftermarket head gasket done was a "sooner or later" proposition as I try to pull some feel-good math of this little journey. *sigh*

Best Regards,

-- Todd H.

Hi

I just went through the same kind of problems

Hesitations on accelleration and decelleration, almost stalling on stops and red lights, lack of power. Problem worse went hot.

The mecanics changed the cam position sensor, o2 sensor, spark plugs and wires and the problem was still there.

They finally took the engine out to check something and found out that the timing belt was off by 4%, I think it had 2 teeth broken or something. I will get the complete explanation monday.

I have driven it for 1 day and it seems to have solved the problem.

Keep us informed

Fo

VERY interesting, and something I'll be passing onto my mechanic as this driveability issue started after he did a timing belt on it. It drove perfectly before I did that $2k worth of preventive maintenance.

Thanks for your post. I'll let you know what happens.

-- Todd H.

Oh, if you could also find out what codes if any you were getting from your check engine light. I'm seeing misfires in cylinders 1-4 and camshaft position range/performance codes when/if my issues get bad enough.

-- Todd H.

I had

misfire on cylinder 1-2-3-4 (right after changing the spark plugs and cables) air/fuel ratio sensor (changed) camshaft position sensor (changed twice) and catalytic sensor (not changed)

If you say it started soon after changing the belt then it may very well be the same problem.

Keep us informed

Fo

Have had these on and off most recently.

I haven't had this 02 sensor code.

I've had this one and had the senosr changed to no improvement.

Had this earlier and it accompanied a catalytic converter that failed a heat test and apparently was partialy blocked. Cat changed, haven't seen code since. One poster suggested (and it made sense) that enough misfires throwing gas into the cat will kill it.

Eerie. I'll keep ya posted.

-- Todd H.

You are a godsend.

I finally was able to get the vehicle back into the mechanic, mentioning this experience of yours, and reminding him that all the driveability issues happened when we changed the timing belt. He'd even seen the TSB on the issue and was very careful to rotate the engine 3x as the procedure states, etc. However, he did indicate that it's certainly possible for the belt to skip after that point and we'd never be able to really see it.

So upon inspection today, he found a tooth on the belt that was not gone--it was just folding over and not holding. Doh.

So he's replacing the belt tomorrow when the belt comes in. We'll see if that finally gets it. He plans to turn the engine manually as many times as it takes until he sees the tensioner pumping all the way out.

Best Regards,

-- Todd H.

As reported previously, turns out I had the very same problem. The timing belt skipped a tooth when it was replaced. The root cause was a defective new Subaru OEM tensioner. This was fingered conclusively when my tech went to replace the belt again and couldn't get the tensioner to pump up and lock out even after 10 turns of the engine (only 3 are called for in the TSB on this issue apparently).

Aftermarket tensioner with a spring backup to the hydraulic action is now on my car and the problem is solved. It's like driving a different car now as I'd gotten so used to how lousy the power was during those months we were chasing our tail playing the ODB-II code of the day game.

I'm not declaring total victory yet though. The car's running great but there is a new CEL since the new rear cat was defected out due to a loose internal part. It's now showing a pending:

P0031 HO2S Heater Control Circuit Low (Bank 1 Sensor 1)

My guess is that with the exhaust work they nicked a friggin o2 sensor heater supply wire. Grrr.

But the car is running well!!! Wee!

Best Regards,

-- Todd H.