1 Lucky Texan

Yeah, I also read something written by a motorcycle engine rebuilder and they also recommend just driving it normal-to-hard. The combustion chamber pressure pushes the rings outward and he feels they seat better with use at near max power.....dunno if that translates to our engines perfectly...but no way would I ignore gd's experience.

if the problem is due to something that gets wetted with fuel, some Techron or SeaFoam in a coupla tanks might help. Also, nect fill-up, leave the cap tight, but pull a hose from the charcoal canister....?

I've seen pics online of 'dropped' (shifted) valve guide inspection after dropping the exhaust. I think it is most common on neglected vehicles.

the other end of the IACV tube is connected and the intake tubes/boxes all secure? I'm trying to connect the issues but, maybe something coincident with low coolant?

the rod knock video I watched...the sound was more and more aggressive with rpm. The video I watched with a weak idler, there were 'nodes' where, the effect would come and go with rpm - sorta cycle in to max vibration, then cycle back down as rpms continue to rise..

what they all said. used oil analysis would show increased alloys if piston slap or bearing issue is the cause. Can also look for fuel dilution. Blackstone labs is commonly used for that. is does seem like a lot of vibration though....could a bad u-joint do this? a dropped valve? hope you find something easy lol!

I believe there may be a Philips bulb with a suffix -LL . supposedly for long life.

good idea to check with an ohmmeter.

CAFE rules kinda force manufacturers to do some weird things. I doubt Ford wanted to make an aluminum truck.....

maybe Mevotech? I have read of folks using the brand on older soobs but, most recommend dumping the ball joint that comes installed for a Subaru balljoint. that's all I can offer.

always check and refresh ground connections on older OBD cars. possible dead spot in TPS range less likely would be a timing belt slip....?

Kobayashi Maru that m,effer!

maybe pinched wiring harness somewhere - in the gaiter/conduit from body to hatch? related to original collision?

hmmmm....maybe pull and compare plugs to see if a single cylinder is the problem and which one? maybe a 'dropped' valve guide or?????

I had a mystery noise for almost 2 years - turned out it was one of the bolts from after accessory belt change - I hadn't tightened it. there's a product called Chassis Ears that might help with difficult noises.

tornadoes are the yanks answer to funnel web spiders

not a thumping? wondering about lower control arm's rear bushing.

likely underhood on an 04, I think earlier models had it on the charcoal canister? 2 wire connector and 2 small evap hoses. maybe near strut tower/firewall? I saw some folks mention it could be near the alternator? sorry, that's all I got from quick search.

purge valves have moved around with model years, but yeah, you have one.

does it also happen parked? seems like heat shields could be a possibility.

more searching online seems to point to the purge valve; https://www.youtube.com/watch?v=ZP5gPigl6NQ

lol, not like I know what any of the results would mean.... between the purge valve and the evap 'drain' valve (connected to the carbon canister) the fuel tank should not have any pressure differential with ambient air so, I think the air moving effect you get when removing the cap 'could' be a clue....?

try a squirt of starting fluid immediately - when it's running rough? at least we'd know if it was fuel-related...? or, next time you feel it would fail, do a few OFF to ON (not START) key cycles. wait for a 3 count at ON, then go to OFF, back to ON, 3 count, etc. - quickly. That runs the fuel pump and should fully pressurize the rails....? you said you can detect a little air movement...wonder what would happen NOT at fueling, but say right now you removed and replaced the gas cap? would it start smoothly?

First time we went to CoSpgs in the wife's Outback, it was weird to park between 2 other Soobs. Here, (back then), that could never happen. Up there, there are as many Subarus on a city block as in a zipcode here.

eh, the debris thing is a stupid guess really, imagine how much anything like that would slosh with normal turning/braking....