1 Lucky Texan

oops! You did say 5-speed. sorry, completely my mistake. When you use the term 'hopping' - is it a jerking motion during/after clutch engagement? Cars are built to boost idle speed when the A/C (and maybe some other) load is presented to the engine. Clutches are also wear items - similar to the material used on brakepads. Any change between the way these systems work might lead to an odd change in take-off like you have started experiencing. If this problem is new, it's difficult to fault your driving style so, I can only suggest there has been a change in either the clutch or the way the idle is boosted by the ECU. Sometimes even throttlebody cleaning will help issues like this but that seems less likely. It may be time to have a good mechanic check for clutch wear/problems and proper idle adjustment when the A/C is engaged.

slow auto tranny engagement? I dunno, probably try doing 3 drain/refill/drive cycles with transmission fluid if it hasn't been changed in a while/ever.

Most people run NGK. I dunno if anyone has reported any problems with Denso plugs. maybe others will chime in. Usually, I just ask questions based on reading posts from the actual smart people! lol! If you do a battery reset on the ECU, it will start the 'learning process' over again. So, might be better to just wait and try a few 'cycles' of running the engine to operating temp, letting it cool off, running again and monitor if the problem is getting better or not.

what brand/number plugs did you use? Do you have scanner that could read the short and longterm fuel trims? It may well require a few cycles of heat-up/cool-down for the ECU to adjust to new plugs.

maybe put the arm back on, put the top back in the knuckle and try;

It isn't 'horrible', just not inspiring from a stop. Highway passing is never a problem, but when my wife and I are in the car and have her jewelry show booth stuff in the back, or any other stuff, you just don't get in a situation where you NEED to zoom from a light, cause the car won't do it. It also has a disconcerting downshift at very high highway speeds. Front diff is a little noisy at medium speed. But it's fine for 'normal' driving. I really like driving it overall. It's glass smooth, visibility is great, rides smooth enough - even with a load, we find the seats to be comfortable, stock radio is OK, the a/c and heat is good, flipping/folding seats gives a surprisingly large amount of versatile space, parks easily. Except for the plugs, it's even pretty easy to work on. I think it positives more than outweigh it's peculiarities.

they have a chain. problems with that system seem rare. HG problems seem extremely rare. WE've never gotten better than 26 mpg on the highway - 25 is more the norm. Around town about 20 (we have an 03 H6 OBW with weather package, not LL Bean, but similar) we run premium fuel - as the manual suggests the known common problems are fairly easy to deal with; Wind noise, power steering noise, valve cover gasket leaks, serpentine pulley bearings, inner axle boot power is up top - great for highway passing, a dog outta the hole. Extremely smooth and quiet engine.

um, it is presently empty of refrigerant? Yeah, a low pressure switch will not allow it to engage as the system may not have enough pag oil w'ever to lube the compressor. If you have already charged it with 134a, how much did you put in? As mentioned, there MAY also be an over pressure cut-out, not sure though.

some newer H4s have a chain now too.

Multimeter is likely showing full voltage. But it can't measure a full 'charge'. If you or a helper measures the voltage across the battery DURING cranking, that 'might' tell us something. I've read 10-10.5 is normal during cranking. If it's a lot lower, I'd suspect a poor charge in the battery or maybe a higher than normal load, shorted windings in the starter or abnormal load or ????? A lot higher than hat, and maybe some resistance somewhere; bad connections, bad cables, etc. Bad cables/connections may be preventing full current during cranking and/or good re-charging from the alternator.

can you get freezeframe data the next time it throws a code? might be interesting to see if the fuel trims are weird on the bank with the 304 (driver's?) side bank.

yep, very easy to miss getting the tabs in at the bottom. probably been making a 'wooshing' or similar noise.

maybe a crank sensor, or sprocket lug got damaged?

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=170854483864&ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649#ht_1211wt_1165

no P'ups, no rangers or S10s anymore. They would clean up with a small pick-up. and a diesel hybrid. Probably should find a way to run the electric on the front axle to get better regen braking, but might not be necessary. Or put the e lectric as part of the flywheel. didn't they have an all-electric kei car in japan? R1e ?

you might check this thread out too; http://www.ultimatesubaru.org/forum/showthread.php?t=132280

fun project! others here will have great ideas but the first 2 things that come to my mind are; EJ22 engine (or built frankenmotor) and a rear LSD from the late 80s. I think the Aussies run Soob-powered sand rails, maybe search the net for how they set those up.

I think some books have an incorrectly low torque value for that bolt. Maybe someone here can confirm the torque for you.

valve cover gaskets?

not much but, maybe run without the TB cover and bolts. find a tiny alt. there's just not much load for a regular one. over-drive it if you have to with a smaller pulley. give him a spare in case it doesn't last long.

do any of the newer plastic intake manifolds move over? any titanium exhaust parts available?

you might 'carefully' experiment with altering the thrust angle so it lifts the rear and pitches the nose down a little. And maybe find a way to boost the Rotax's output. If the engine/pilot can't move, could the fuel and/or any on board battery be moved forward? (battery would be best as it is a static load)

should be able to trim a LOT from a flywheel as I imagine there's a lot of flywheel 'effect' from any attached prop. but yeh, 50lbs is a lot. maybe higher octane fuel and more compression? smaller radiator? motorcycle battery?