1 Lucky Texan

if the car is dieing in traffic - definitely report that to NHTSA.

in theory - overfilling up near/past the 'windage tray' or w'ever, 'could' lead to oil being beat into a foam by the crank shaft - foam is not pumped as well by the oil pump. but with a HUGE amount of overfilling....and, for such a short amount of operation....I kinda doubt there's anything to worry about. You might consider asking for new oil filter and PCV valve - maybe even a throttle body cleaning....???? I doubt anyone could quantify any reduced utility from the car though. does the engine 'only' last 275,000 miles instead of 300,000 ? impossible to know.

strut bearing? If you can duplicate the noise at low speed, maybe have a helper maneuver the car while you pace it and listen. there are enough possibilities that you likely need a pro to help diagnose this.

what dealer?

^^^ if the front and rear final drives are the same, either age/bad luck took out the enter diff - or the car has been run with a mixed size of tires lonf enough to damage the CD.

could this be a cabin air filter issue?

can you crank the engine around with a wrench? maybe check for slipped cam/crank timing.

kinda want to ask about the plugs - are they the correct part number? did you check or adjust the gap? re-check for oil in the plug tubes? looks like you are very close to needing a timing belt system service - kinda wonder if cam timing could drift enough to cause problems if the tensioner is weak?

try this, put the trans in Park or N, then, foot on brake, shift to D if you feel vibration when in D, 99% it's the axles. not uncommon for rebuilt or some new aftermarket axles to cause some vibration. usually reported at stopped at idle but, i gotta believe it 'could' also happen while driving...?

read these;http://forums.nasioc.com/forums/showthread.php?t=735058 http://forums.nasioc.com/forums/showthread.php?t=1944699 http://www.clubwrx.net/forums/maintenance-service-repair/134297799-cel-p1596.html

^^^ yes, gauge readings are subject to 3-4 moderating factors. cam overlap and timing, altitude/local atmospheric pressure, temp, etc.

mutiply the cr and atmospheric pressure ? if cr = 9.7 and atmo = ~ 14.7, that's a little over 140psi. i've read you want cylinders within 7psi of each other too. dunno how low you draw the acceptable threshold...

are you able to scan the ecu for DTCs ?

this could easily happen if the transmission pan was dented - or maybe just 'deflected'. damaging a solenoid. 2 or 3 other possibilities i guess. Try a search, kinda common code after engine/trans work actually.

that's bad news - I'd expect it would be easy for RA to get the supplier to reimburse them for the return shipping. Certainly YOU shouldn't be on the hook for it.

vacuum leaks, bad wiring,etc. , all that needs to be considered as possible P0420 causes. If it comes down to the cat, you might consider a low miles unit from a junkyard - California cars may not have killer rust and swapping-in an OEM cat should be doable. You may find one with 1/3 the miles of yours at an affordable price. car-part.com and LKQ are possible sources. I think there are ways to use an infrared thermometer and perhaps determine if the cat is lighting-off - check youtube for that.

if you think the engine is now flooded, try starting with the gas pedal held to the floor - that causes the ECU to go into 'clear flood' mode. could the security system is preventing start(?) try lock/unlock with the key fob.

things as simple as an exhaust leak or cleaning a MAF sensor have cured that code for folks - we often tell people that the cat is rarely the problem but, at 340K, yours may very well be 'done'. Same for the rear sensor. worth looking around for other issues first as even aftermarket cats are pricey. Some folks also have use - spark plug 'extenders' and resistor networks to turn off that code. The rear sensor that triggers it is ONLY used for cat monitoring and has ZERO effect of the car's running parameters.

yeah, good luck ducking in to remind you - weak tb tensioners can sound like rod knock or piston slap sometimes.

oil sender is on top, kinda under the alternator - worth a look if you think oil is coming downt he front.

I assume you have an automatic? What year? anyway - you're likely to overheat transmission fluid and some vital parts if you tow it. The FWD fuse only 'works' when the engine is running. the 5 spd can be towed - best if done slowly for limited distances I think.

all 4 tires really must be the same brand/model/size and close to each other in wear. You use the FWD fuse when you install the donut spare. There ARE ways the system can fail even when you do all that correctly - Duty Solenoid C can be bad, wiring can be bad, the wet clutch pack can hang-up and not function correctly, etc. you may have 2 or more problems, but it seems one of them is definitely torque bind. If it continues, the transmission can be severely damaged. If the FWD fuse is NOT in place, put a fuse in there. If you do that and STILL experience torque bind, might be best to have a Subaru experienced mechanic determine what the problem is and if the best approach might be a used transmission swapped-in.

jerking/bucking in tight maneuvering on dry pavement. (the car should be able to turn tight circles smoothly at idle, or just above idle speed) as a test, there should be an empty slot in the fuse box under the hood. Placing a fuse in there will place the car in FWD mode. Check you manual - usually under spare tire use section. Often, that will make a change in the way the car behaves and point to certain problems in the transmission or drivetrain.

^^^ yeah, with pinion and spiders and old tripod/DOJ joints - 1/2" doesn't seem bad.

all the kits work to a fairly good degree. The 'secret' seems to be a thorough cleaning after, followed by a good UV blocking clear-coat. what types of bulbs are in your car? there may be an option but, most brighter bulbs will have a shorter lifespan. Don't do HIDs without proper projector installation. check State regulations before adding additional 'offroad only' driving lights.