1 Lucky Texan

I think he replaced the rotors. one possible point of confusion, you adjust the star wheel UP to tighten the adjustment on both sides. seems weird but, there's even an arrow embossed onn the brake shield back there.

hmmm...starter was changed (probably cables inspected but...?) so, yeah, some security 'feature' is suspect. maybe the switch on the brake pedal?

what would happen if the HGs were swapped side-to-side? or installed 'reversed'? any return passages blocked or are they perfectly symmetrical?

any sign of oil loss or oil in the breather tubes or intake tubing? I once read of an STI owner that had misrouted PCV and breather hoses when reinstalling his engine = ended up with an oil pressure light on from pulling a vacuum on the crankcase!

wow - almost seems like the oil can't drain but - dunno about how loosely they seem to fit. interested to read more comments.

20 year-old car is expected to need a 'sucky' repair every few months. while warm and idling, try tugging/pulling on some wire harnesses and hoses under the hood - maybe a vacuum hose is cracked (even a vacuum gauge might be useful with this problem) or a ground or other wire/connector is intermittent. Does it feel like the car is 'pulling' when this happens? maybe a Torque Converter issue?

torque bind stresses the entire drivetrain, who knows if a u-joint or something else has been compromised?

I wonder what a system would feel like if there were air in the ABS pump? how is that system bled?

a 98 in Indiana could have rusted lines - any loss of fluid or drips from the gas tank area?

one option, you might find an entire trans out of a wreck (LKQ or car-part.com) ,maybe with less miles.

there's a way to measure the tires with some chalk and a run on some pavement, but maybe you can get a new tire to match the other 3 new ones you're picking up? some people have found a single, slightly worn tire on ebay or craigslist to match a partial set after a sidewall blow-out. (will FRS rims fit on your car? same bolt pattern?)

Subaru has recommended for decades that tires be within 1/4" of each other in rolling circumference. Reality seems to indicate the system may not be quite as sensitive as they want you to guard against but, any tire (axle actually) turning faster than the others could be sensed as slippage and cause the AWD system to begin engaging. the fact that there are different tires on the car may also point to prior abuse of the system by mixing tires.

hmmm, the different brands 'could' be contributing to the issue... as an experiment, put the same brands of the tires you have on each SIDE (or opposite corners) and see if there is any improvement.

Impreza is a lighter car, but, maybe the tires are over-inflated? Did you buy it used? maybe the prev. owner modified the suspension?

maybe ask/dig around at NASIOC and subaruoutback Forums.

did the car have normal feeling brakes in the past? any work done or wrecks before the problem began? inspect all the brake calipers and caliper brackets. are all the brake pads wearing evenly? any wedge-shaped? brake lines bled of air? any damage or major rust around the firewall where the MC is mounted? after idling the car, pull the hose off the booster, there should be a woosh of air go into it. If not, it could have a leak? (I don't guess it's possible the booster hose is on backwards? maybe test by blowing into it - should block blowing from the engine side)

just to be clear, all 4 tires are exactly the same? brand/model/size? did the po swap any parts? rear diff or transmission?

guess there isn't a CD stuck in it.

did you use the 'line' indented on one of the 'tabs' at the rear of the crank sprocket? Or, did you use the 'triangle' (some call it an arrow) at the front of the crank sprocket? (you MUST use the line. and none of those tabs can be broken off) the 'tooth count' referred to is the number of teeth between the various pulley index marks. Not a bad idea to use the wrench to turn the system trough 2 revolutions, stop at the cam/crank timing positions, then count the belt teeth between the marks and compare to Subaru numbers. also, the car could be flooded - if you suspect that, try starting while holding the gas pedal on the floor. That signals the ECU to cut fuel.

rebuilt axles are notoriously poor in quality. if they are truly 'new' (as in, new Subaru axles) I would trust it isn't a cv joint. But rebuilts often have the case hardening ground away, cheap over-size bearings dropped in, cheap grease added, etc. maybe 1 out of 10 will last. just make certain it IS the diff before proceeding to swap the trans or w'ever..

swap axles side for side to confirm it isn't the SOJ/tripod joint. inspect brakes for binding caliper. (woner why the front diff got rebuilt - anyway, there's tricky diff preload procedure I think and it may have had a short lifespan if it wasn't properly rebuilt.)

did you have the battery disconnected? sometimes a security system can lock you out - try locking/unlocking a coupla times with the remote.

fuel pressure regulator? or did new one come with replacement engine?

does the car have a filter spun-on the side of the trans? or, is it remotely mounted like our 03 OBW? anyway, you may need a new filter if it's waterlogged, it isn't an oil filter, built differently inside - that is, you need one from a dealer I think. or, if the TC was stored outside, maybe the filter is now clogged and excess pressure is pushing the fluid out?(dunno if the trans filter has a bypass)