Yes, have the receipt for the TB change, which was indeed done at 100,000 miles (160kkm). Local dealer did it.

Thanks for the thought!

J

If you'll forgive one more SWAG: I believe all modern engines have controls to detect and prevent "pinging" (pre-ignition). I think the control method is to retard timing. You mention that some pinging seems to be associated with the problem. If the engine has a significant buildup of carbon in the heads, and on loading (hill climb) it occasionally begins pinging, the engine controls will compensate resulting in some power loss. As I said, a SWAG.

Update:

Stopped into the dealer from whom I purchased the car today... Miss has worsened in the last few days, but still no clues (plugs look fine (all platinum or irridium NGK's, white insulators, no trouble signs, no CEL, nothin).

Appt. with Subaru dealer tomorrow for diag.

Dealership agreed with bringing it to Subi dealership, and asked that I get just the diagnosis from them, and bring the car back to them so that their mech (who lacks engine analysis equipment) can make the repairs, at their cost. This seems, to me, to be a reasonable arrangement. I hope they are as good as their word.

This has been extremely stressful thus far, and my confidence is somewhat shaken.

J

Hope they nail it for you, but if they don't, try a tankful of premium gasoline.

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Stressful, yes, but at least they're goin the extra
mile to take care of.....??

Odd that a misfire doesn't show as a CEL.... it should.

.

Agreed. It _should_.

J

Well... No solution yet.

Subaru dealer's opinion is that it's likely a mechanical, rather than fuel or ignition problem, their reasoning being that EFI or ignition problems would result in a CEL.

They believe there is a mechanical problem. They suggest starting with plugs and fuel filter (just because they're probably due), check the timing system, drop exhaust manifolds to check for a "dropped exhaust guide".

Delivered their opinion and the car to the used car guys. They asked that we give'm a couple days to look into it. I said I either need it fixed, or they need to take the car back. He said we'd discuss that with the owner should we come to that.

*sigh*.

I had a chat with my step father who has a long history in auto racing and engine building... And who has one of the US's most reknowned specialty auto mechanics visiting him right now... Perhaps they'll have some thoughts to add....

J

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Hmmm, interesting.

On what did they base their "opinion"?

I know finances sometimes dictate the need for such purchases, " But my dad always used to say, buying a used car is usually buying someone else's problems"

My dad used to say that too, but years ago, when I was getting my kids through college, I bought nothing but used cars. Yes there were some problems, but I got a lot of miles out of those beauties. Most fun was a Merkur XR4TI. For the Winter I picked up an old Plymouth K car. The Merkur was horrible in snow and ice, just left it in the garage and drove the Plymouth in the bad months.