[donavan]

So this morning after changing the belt tensioner on my AC belt (stupid me broke it cause I forgot to loosen the nut). Anyway, I got the belt tight on the the AC and after little while of driving, I have noticed that the engine seems to bog down a lot when the AC compressor kicks on. Its intermittent so I can't be sure but was wondering if anyone else has had any issues with the AC compressor going out and causing this sort of issue.

 

[Bravo12]

Sounds like my problem is more common than I thought. My valve cover gaskets have been leaking for awhile, and I suspected that might have something to do with the ignition stumbling at low rpms on uphills in extreme heat.

 

[exume]

Oil is not a good conductor of electricity.

A/C on is mechanical load. So yes if you have a problem it will be there more with the A/C on.

 

[dwmoss]

I searched .... the IACV is 22650AA192 and lists for $345 from Subaru. If I needed one, I might just go to Ebay and buy an entire used throttle body with one on it. I see the entire throttle bodies for under $100 with the TPS and IACV at a minimum on them.

Before anyone goes out and buys a new IACV.

There is a IACV cleaning procedure on nastysock. Peaty also has the endwrench article on ISC (as they call it) cleaning on scoobymods.

I just got back from a 2 week holiday, my wrx sat the whole time. It had a really bad surging idle and came up with a p1507 cel. I did the iacv cleaning procedure and so far so good.


dm

 

[ferret]

The 2003 Outback above ... CAME BACK ....... and NOW I'm CERTAIN it's fixed. Here's a thread I just posted ..... and since BOTH you Dave and the OP have manual transmissions, you might look into this:

http://www.subaruforester.org/vbulletin/f88/neutral-switch-78655/#post870591

 

[Bravo12]

Update: new plug wires cured my problem. 600 miles into a 900-mile road trip (all highway), the sputtering was getting worse in 5th gear when hitting a rise in the road. SO, I stopped and wiped the oil off the front spark plug boots; I couldn't get to the rear two without moving the air intake on one side and the washer fluid reservoir on the other. But, while there was some oil from the leaking valve cover gaskets, it wasn't nearly as much as I had expected, and definitely not enough to saturate the rubber boots.

A little further down the road, I found an AutoZone, and decided to just try putting new wires in (after seeing how easily it could be done on the 2.5 N/A motor). One set of Duralast wires for under $30, and 10 minutes of work, and I was back in business. It runs like a champ now, even 400 miles later.

One note (and maybe the source of the original problem): One of the wires came apart when I took it off. The inner connector separated from the boot and the wire at the distribution block. Luckily, it was up top and easy to pull the metal connector off. I guess it's possible that it was already coming apart, and the connection was iffy.

Anyway, pull the wires at the top and make sure they're not coming apart. On a side note, does anyone know for sure if the motor needs to be pulled to replace the valve cover gaskets? That's the only major issue with my Foz now.

 

[rilles]

I recently had an issue of stuttering and shaking at idle on my 2003 RS that kept getting worse. Went to replace the plugs and found that two of the plugs had oil all over the top and there appeared to be no electrode left (crappy bosh plugs the issue here).
Replaced the valve cover gaskets (easy as changing the plugs except you have to take the battery out to get more room) and replaced the plugs with NGK and my idle is nice and smooth now.

 

[tlm1956]

I just purchased an 01 Forester / manual / 115k and it recently developed the same problem. It had a new catalytic converter (not sure about O2 sensor) 1k miles prior to my purchase. Problems since fuel filter (not OEM Subaru part) a few hundred miles ago.

Car runs fine, 30mpg, then will go 'whoomp', 'pop' stumble and finally smooth out again and mileage drops to 15mpg. Idles at 500/700 running good or bad.

Would like to take to dealer for 120,000 mile service to be checked and for records, but would like to have the 'surprises' known/repaired first.

Fuel issues? Get OEM fuel filter? Is there another fuel filter in tank or somewhere that could effect this?

Hope you get your vehicle worked out, I love mine.

 

[MudRunner]

OP's problem sounds like a TPS failure to me... a lot like what my car was doing when mine was bad. Shifting erratically, and acting odd off throttle and at idle.

Also, 'erratic' problems can often be caused by a loose grounding wire. I found that out the hard way... so check all the grounds on and under the intake mani to make sure nothing is loose. :shrug:

 

[chrisadsti]

Hey Guys, I hope you can help me with this.

Now, I have a 2004 Sti, but, I do have "the surge". It occured anywhere from 1800 to 3500 rpm, worse at 2400 rpm, BUT, only at VERY small throttle or on the over-run.

I first noticed this 18 months ago, but only when starting from cold, and it didnt seem important, but it has steadily got worse, and now occurs when warm.

I took scooby to a respected Subaru specialist, from whom I originally bought the car, a 400 mile round trip, and they said nothing showed up, and suggested changing the air flow meter. That done, the car is smoother overall, but the fault is getting worse. The surging now occurs from 1800 to 3800 revs, still on almost closed throttle only as before.

Now this seems to me to be a throttle position related fault, can anyone point me in the right direction to cure it ??.

Please !!.

VBR Chris Adams.

ps: the car is a 2004 Forester Sti. ( 2.5L Turbo, Japan and New Zealand model ).

 

[ferret]

I will update this thread as my diagnoses progresses.

After fixing many a Subaru for idle problems ... now I have had a phantom and not everyday one for a month or so. At first I thought I had bad gas. Car always starts, but from a cold start, after a few miles, if I stop, idle was very rough, I sometimes had to step on the gas to keep the engine running and the exhaust smelled REAL BAD. If I let the car set a few days, it seems to take a longer warmup time before I have a normal idle.

With an OBD reader/monitor I would only see the O2 sensor go nuts ..... that's why I started there. Was it the Cause or Result? Turns out it was the result. Also I had PENDING misfires on all 4 cylinders. P0301, P0302, P0303 and P0304. Never went over the criteria for a misfire, but always pending.

I tried a new front O2 sensor, Engine temp sensor, swapped AIS, TPS, Air Temp Sensor, Map... All no help. Neutral switch was BAD ... always open telling ECU I was never in gear. Again no help there.

Over this weekend, I though about it. I had removed the EGR and cleaned it when I did my engine rebuild last year. ( http://www.subaruforester.org/vbulletin/f88/every-2-5l-interference-engine-64410/ ). Being an ELECTRONIC EGR with a stepper motor, there is no way to see or test if it is open or closed. And at almost $200, I wanted to be certain. So I took an aluminum can, cut it and laid the EGR gasket on top of it. Then I cut the outline and used a hole punch to ONLY punch the bolt holes. Put it in and started driving.

Since Sunday, my bad idle has not returned. I DO get an expected CEL P0400. Happens during the EGR test. About 5 mins into a start, while decelerating ( fuel cutoff time ) the ECU opens the EGR and expects a DROP in the MAP value. With my aluminum plate in place, this obviously does not happen.

So later today or tomorrow, I will bite the bullet and order an EGR. After further searching the internet, Mitsubishi's use a similar valve and their boards are full of bad idle problems caused by it. The Mitsubishi versions however is more than $400 .....

Something to think about if you have any Subaru with this type EGR and an intermittent bad idle problem.

Item #11 in the following Illustration:
http://opposedforces.com/parts/fore...11/type_3/intake_and_supply_system_turbocharger/intake_manifold/illustration_1/

Pictures attached ... 1st is the EGR on the engine
2nd is the valve, gasket and cutout blockout aluminum from a can
3rd is the valve with the gasket then the blockout and bolts in place ready to be put back on..... and smooth my idle ......but give me the P0400 code.

 

[ferret]

UPDATE to above ..... since Jackie at Annapolis was out this week, I ordered an AIRTEX / WELLS replacement from Rock Auto.

2008 SUBARU OUTBACK TOURING 2.5L 2458cc H4 FI [EJ253] SOHC Emission : EGR Valve Auto Parts

More Information for AIRTEX / WELLS 4F1846

Came this morning .... guess what, in the box was a SUBARU part complete with the Subaru Part number on it. Replaced it and have done over 50 miles so far ..... No more P0400 due to my block ...... and idle is smooth all the time.

This really looks like my fix ...... will dissect the old valve next week when I get time.

 

[ferret]

Now firmly convinced this WAS my problem ..... 2 more days of great running. Better than it has in a while. And I had the time to take apart the old EGR. Now certain it MAY be repairable for this type of problem. Pictures explain it below:

1st picture the valve with the 4 screws removed

2nd picture, the bottom of the stepper motor. It moves downward to PUSH the valve open. Then moves upward to ALLOW the spring to return and close the valve.

3rd picture, look into the bottom hole and you can see the plunger. This means the valve is open. The spring is not enough to overcome the shaft binding and close the valve. When the valve it closed, the plunger is seated and you can not see it in the lower hole.

4th picture, from the top, the spring compressed and valve open. Shown in the failing state.

5th picture, the spring as it should be, extended and the valve closed.

Last picture, instead of making the aluminum blocking plate I described above, you can unscrew the top of the valve, while on the engine. Make certain the valve spring is ALL THE WAY UP, and the motor on the top off to the side. This will still set a P0400 code, but give you another way to see if a sticky EGR is the cause of your bad idle.

By the way, I cleaned the shaft inside the upper hole, and used high temp silicon grease on the top shaft, under the spring, and in the upper hole, working it back and forth and have a working SPARE EGR,

 

[nikos]

Is the EGR under the intercooler on a turbo engine?

 

[ferret]

Is the EGR under the intercooler on a turbo engine?

As far as I am aware, there in NO EGR on the 2.5L turbo.

 

[kenetics]

interesting! i'm having a problem with the idle of my forester now. the engine turns off while in driving (stop and go) in traffic. i'll have my local shop check if my engine has egr. i'm i correct that engine with egr are sohc engines? i have 2000CC DOHC TURBO engine, i was wondering if this engine has egr?

 

[kenetics]

btw, my forester is a 1997-1998 s/tb model.

 

[MN2001ForesterS]

I've had the same problem getting progressively worse since Thanksgiving 2010. Now my 01 (2.5 NA, manual trans) has had all of the symptoms described by everyone in this thread. Cold (long cold overnights) the car starts up and revs high in a warm up cycle, then slows to normal idle after about 3-5 minutes. Once warm the car starts out fine, but then begins to act funny.

Give it gas in any gear and it bogs down no matter how hard you are on the throttle. No throttle feedback on the power end. Doesn't matter what gear I'm in, either.

Disengage the clutch and give it gas? Revs up just fine without hesitation. In gear? Slow, stammering, hesitating. Under load (uphill)? Even worse. I even had the engine pop what sounded like a misfire/backfire.

At idle it surges below normal and back up again. It stammers and sputters out of nowhere if I'm driving on the freeway like it isn't getting gas. But again, disengage the clutch and give it a rev and it acts like nothing was wrong.

Now here is the thing. NO Check Engine light has come on. Ever. Code reader shows nothing. Nada. It had a Check Engine Light for a rear o2 sensor, but that has gone off on its own and I cleared it. Hasn't come back since.

Where on earth do I start with this engine? Do plugs/wires? Then what? Is there a "fix" that I can do without much Suby tech savvy? Or do I have to take it to the dealer and take it up the tailpipe? I imagine it is the EGR valve, but I can't find a replacement part online anywhere. Is it a job I could do myself with hand tools?

 

[mrr1]

hey - Donovan - any joy with the car? My wifes 2002 NA auto is doing exactly the same. I've posted a few threads on here but no advice yet. I'd be really grateful for any hints.

 

[Bravo12]

Mine is at AZP Installs right now, with the same problem. (I'm actually here to get one of my wheel bearings replaced, but it was stumbling all the way here so they are gonna try to diagnose it.) New coil pack installed, and it still shows misfire on #1 cylinder. Once the wheel bearing is done, they're gonna pull the plug and check the gapping on it. I'll update here as we go.