G'Day All.

 

I have a 1991 Subaru liberty with an EJ22 engine. It has a manual transmission.

 

When under sustained load (accelerating up a hill) it loses power and RPM starts to decrease. If I try and accelerate through the power loss, the engine only loses more power. Changing down gears also does not help the problem.

 

When it starts to lose power, if I pull over, the engine vibrates and feels like it is running on 3 cylinders. No codes are displayed at any time.

 

If I let the engine idle for a few minutes, the engine recovers and performs as per normal. 

 

I have replaced the following items:

 

MAF (cleaned)

Fuel Pressure Regulator

CAT

Fuel Pump

Fuel Filter

Spark Plugs

Spark Leads

Oxygen Sensor

Knock Sensor

Coil Pack

 

I have also run it on 98 Octane Fuel. I have run an upper engine cleaner through it and a fuel cleaner through it.

 

It has had multiple oil changes.

 

Does any one have any suggestions to the problem. I have done a significant amount of study and no one seems to have a comprehensive answer.

 

Cheers.

 

Sounds like the symptoms our 91 Postal Legacy had. Decided based on a radio show that the valves were sticking open when the engine heated from load, so it would gradually lose compression.  Fixed it by using an oil additive that cleaned the valves and a decarbonizing gas additive, but it sounds like you've already tried that? Did you try adding something like Seafoam gradually into the  intake manifold?

I have only tried an off the shelf product without much input from anyone else and I wasn't really sure which one to choose.

 

Can I please ask what the products were? The Oil Additive and the Gas Additive? 

 

I am down in Australia and will see if I can get my hands on some SeaFoam. 

It's been years but I imagine the oil additive was something like Motor Medic Valve Medic. The gas treatment could have been anything that mentioned valves. I didn't use the Seafoam that time, but have used it since too decarbonize cylinders, after having seen it used on Youtube. Sorry I can't be more helpful. Maybe someone else will have better or more specific suggestions.

Thanks for your help. If anyone else has any other suggesstions it would be much appreciated.

The number 4 cylinder is often the culprit.

Ok. Thanks.

 

How would you recommend correcting the problem?

 

Thanks for your help.

Check out this thread, 

 

http://www.ultimatesubaru.org/forum/topic/18095-1993-legacy-gremlins/

 

Experiencing similar problems with my 1993. Unfortunately I have not been able to do work on it much lately as it is located out of town. As far as things to check, yours does sound electronic but just to eliminate, I would do a compression test as well as pull the timing cover and check the belt. Make sure it hasnt jumped a tooth or two.

Also btw, BG 44k is an excellent fuel additive that I have seen personally do "miracles."  Look for it on Ebay. Usually about $20 a can

Great. Thanks for that. Looks like, after reading the other threads, Marvel Mystery Oil, Chevron injector cleaner and the additive you suggested might be the go. I'll also put some Sea Foam through the intake and see how it goes. Timing belt looks fine and hasn't jumped.

The number 4 cylinder is often the culprit.

Moosens, Have you had luck with correcting this issue at all?

No , we ended up getting in an accident with that car and dumping it off. I recall a top notch master Subaru tech telling me about this issue. I know its awkward for many people but see if you can go by a dealer and get an older tech off to the side. They'll be able to explain it better. Something to do with the manuacturing where that last valve sits out and gets more cold and condensation .... causes it to stick.

 

Correction would require some labor for sure. Valve job or head replacement most likely.

 

We would get on the highway entrance ramp and have the SAME problem act up in almost the exact same place every time. I had thoughts that there was something external causing it like some sci-fi magnetic force ...LOL I swear it was happening every time and in the same spot.Once we'd get past the next mile or so it'd improve , but not without sometimes having to just pull over and let it correct itself at idle. VERY annoying.

Thanks Moosens. I'm in Aus and have ordered Sea Foam and the additives described above from EBay.

 

Any further advice would be greatly appreciated including which additives to use.

 

Anyone else with ideas or solutions please let me know.

 

Cheers.

 

Ryan.

I don't think any additive will help , but maybe it'll loosen up that valve enough and leave a coating on it your oil doesn't , so it won't stick.

 

I'm not opposed to trying especially since trying the least expensive method works best on the budget.

 

We've heard various causes , some of which you've covered already. "Crack in the coil pack ' , "arching spark wires" , etc...all possible. But you've done your best to eliminate those I see.

 

You guys get New Years before us so have a GREAT one!

 

Cheers!

Completely agree. I'll give the additives a go as I really don't want to remove the head.

 

Thanks for your help mate. Happy New Year!

Would a sticky valve show up on a vacuum gauge?

Hmm not sure? Maybe only when the issue is replicated... Under load up a hill?

One thing I have noticed is that the majority of the additives attempt to remove build ups from the intake valve but then get combusted in the chamber so they don't do much to the exhaust valve. Does anyone know how to gradually remove carbon build up from the exhaust valve without removing the head?

Hi All. Just a quick update.

 

SeaFoam added through the intake and through the fuel system. Still experiencing the same problems. No change.

 

Anyone else got any ideas short of removing the head?

 

Cheers.

Did you try an oil additive?

I have tried one where you add it immediately prior to an oil change and just let it idle for ten minutes but I would like to try one that you leave in permanently. What would you recommend for this? MMO? SeaFoam? Or any other suggestions that will help?

Has anyone had success with Marvel Mystery Oil?

Marvel's MMO is great for loosening up sticky valves, stopping the "tick-of-death!"  But I wouldn't leave it in permanently.  Dump a bottle in your crankcase 50 or 100 miles before you plan to change the oil, then drive like normal.  I've seen it work.

 

Good luck.

Great Thanks!

Great Thanks!