[Both head gaskets?]

I say thou art answering specific questions with generalizations. However...

 

Let's assume that when you "lightened the flywheel", you didn't somehow affect the crank reluctors or sensor (the degree of engine loading might cause their physical relationship to change enough to momentarily lower sensor output, if there's sufficient play).

 

"Good" engine operation requires a free-flowing exhaust, a free-flowing intake that can be throttled as needed, and well-sealing valves and rings so it can pump efficiently. Bad head gaskets can throw some of that out of balance. If you snap the throttle shut after revving, the closed throttle should cut off most air (which indirectly should cause most fuel to also be cut), and the engine revs should drop rapidly while the intake vacuum jumps up. Slow response to a rapidly-closed throttle could indicate a vacuum leak, or leaks at the injectors, etc.

 

A vacuum gauge (and the knowledge to use it and interpret readings correctly) might help quite a bit in resolving things. On the other hand, so might a new engine.

The WRX's come with new engines don't they? Blasphemous, considering I work at a Chevy shop. I do have limited mechanical abilities of my own, but I can borrow a vac gauge for the weekend. The injectors are super easy to get out. Someone on here awhile back suggested my 3&4 missfire records may be a result of resurfacing my flywheel. They started coming on almost immediately after we did the clutch here. He said the flywheel may spin too fast on a decel, throwing off the crank sensor readings. Nothing sounds too far fetched to me anymore with OBD2 stuff.

[Both head gaskets?]

I haven't noticed anything unusual about the idle other than the fact that if I rev it at idle, it seems to hang awhile before dropping down. What say ye?

[Both head gaskets?]

I haven't noticed any temp gauge fluctuation at all. I get whiffs of coolant after I get out and can smell the exhaust in the overflow. In 3000 miles it just emptied the overflow, radiator level was fine. My engine light is a constant companion, I figure it records the misses on decels because that's when the light flashes. As soon as I tip into the throttle, the lamp steadies. I've replaced the ignition coil, plugs, and wires, still the same. Thanks for the input.

[Both head gaskets?]

I was sure I'd get at least 200k out of my 98 Forester. I've had missfire codes on 3 & 4 since I lightened the flywheel, figured that's what it was from, I never feel any missfires and they only set when coasting. I took it in to our local dealer for routine timing belt replacement, they called and told me that I had missfires recorded on all 4 cylinders and a cat low effeciency code was current. I could get them both done at emplyee rate for around 1200$, including the timing belt stuff. I just don't see putting that money into a 194k engine. I told them not to do anything. Ive had it back for a few weeks and have scanned it a few times. The only thing that comes up is the same old 3 & 4 miss. No cat codes. I don't think it can even run the cat test as long as missfire dtc's are set. There's something going on though because I have higher hydrocarbon levels in my coolant overflow bottle than a model t has at the tailpipe. Any idears out there? Do both head gaskets sound logical or is there a common quirk nobody is sharing with me? Thanks

[Forester ground clearance]

Anybody have any experience with putting larger tires on a 98 era Forester? I want to gain some clearance without wrecking my t-case or something.

[98 Forester mystery missfire codes.]

Yep, they resurfaced it. I oredered a new one today. Nobody at Subaru, service or parts, has ever heard of this. I did some research after you brought it up and I now know I'm not alone. I should start a support group or something. I'm just happy to finally be driving it after 4 years of making payments on it. It's been my wife's driver and she never really liked it. We just got her a new Suzuki Forenza (sorry but it's the most car for the money) and now the Forester is mine.....all mine!! My 72 Datsun 510 isn't too fun on the Oregon roads on dark winter nights, so it gets to hibernate now.

What did they do with the flywheel?

 

Surface it or replace it?

 

Chances are they will not have heard of this before. Don't be surprised if they think your a little crazy. Good luck.

[98 Forester mystery missfire codes.]

I'm a service writer at a Chevy dealer and bought everything myself so I know that's ok. But, I think I could get them to do a parts warranty on the flywheel. It makes sense. Your advice might just save my sanity. Thanks again. sb

First off, make sure 100% that the parts we're purchased from a dealer. I've seen many shops claim to use oe parts; then to find out later they we're aftermarket. Did you do this job yourself? If not then I would want to see a receipt from the dealer on the parts.

 

What was done to the flywheel? Was it surfaced or just "whizzy" wheeled clean? This balance issue is very hard to confirm. If the flywheel was turned; and oe parts we're installed I would install an oe flywheel. Subaru does not recommend flywheel surfacing. I know a lot of shops and dealers do it. Basically the mis-fire monitor on the phase one 2.5 is too sensitive. Good luck.

 

Color-blind

20 year Subaru tech

[98 Forester mystery missfire codes.]

When we had my transmission out for a leak, we replaced everything with oem from the dealer. Could the flywheel just be out of balance?

The ecu monitors for misfires thru the cam and crank sensors. If their is a problem with thier relationship it sets mis-fire codes. This is a difficult diagnosis to determine; you should also check the valve clearances on the cylinders that have the mis-fires. If valve clearance is good then do the following; replace the clutch assembly with oe parts and install a new oe flywheel. Subaru will have all these parts in stock. Basically you are having a balance issue. Been their done that. Good luck.

[98 Forester mystery missfire codes.]

Why, as a matter of fact, it was. Not long before this all started, I just never imagined they'd be related. Please elaborate. Thanks.

Is your Forester a 5-spd model? If it is, was the clutch replaced recently?

[98 Forester mystery missfire codes.]

Nothing non-stock except a Bazooka 8", usually talk radio (like that needs bass), but it only takes a second to unhook it, so I'll try it. Thanks.

Shot in the dark: If you have an overkill stereo system, it can misfire when bass hits coincide with low alternator RPMs.

 

Even if you don't have a 5kW sound system, I'd consider replacing the battery if the battery is marginal.

 

Or just live with it. Don't pull the head.

[98 Forester mystery missfire codes.]

I'm at the end of my wits with a consistent missfire code on 3 & 4 on a 98 Forester. I have done plugs and wires, coil, top engine clean, injector clean. When the light flashes, then sets, I feel nothing, no missfire at all. It's usually on a fwy offramp or down a slight grade, not really into the throttle. The local dealer didn't give me a feeling of confidence after it sat there 3 days, pretty much went over what I had already done. They suggested a valve problem and want to pull the head and go from there, but are not willing to stand behing their guess. If they're wrong, I still pay. Am I missing something or are they on the right path? I surely appreciate any advise.