Installed the TPS (70$), runs much better.  Not perfectly smooth, but
not bad for 200K miles.  There's no IAC on my model.  I may replace
the fuel injectors eventually but it seems to be improved a great
deal.  Many thanks for the tips, MUCH appreciated!
~GJ~

do you plan to replace the TPS and IAC ? (throttle position sensor, idle air control
sensor)
cost for both parts under $90 total and you need a simple screwdriver or small wrench,
no special tools, about 2 minutes to replace

The transmission seems to work so far.  Engine still idles rough but
doesn't die.  I was told that a misfire was showing up on a scan but
took it to advance who checked it for free and the only thing coming
up was an egr error-bad air flow.  I've recently replaced that and the
code keeps getting cleared out, so I dunno....?  Idles bad though.
~GJ~

how does it run and what issues were resolved?

It's ready, but I get it back in the morning.  
~GJ~

did you get car back? did they fix it and any other discoveries on their
part (or your findings)?

160K

I bought it with 120K on it.

I will try that, when I get it back next week of course.  Turns out in
addition to the leak, they put a new faulty TC on it, they say.
~GJ~

Gemini, lemme get this right...2001 3.5 Trooper - roger on the oil
consumption - welcome to the 3.5 oil guzzler's club. Looks like you've
replaced most everything that would cause poor engine performance, except
for that which would cause one spark plug not to fire, which is a vacuum
leak. Or possibly that coil, but can you tell us how many miles are on this
engine? My 98 has nearly 100k and is running strong, with the same coils,
same timing belt, same everything it had on it when I bought it with 44K on
it... but intake manifold gaskets are a known problem with these engines (in
addition to lousy gas mileage and high oil consumption). And a leaking
intake gasket could make the noise you hear on startup, loss of power, etc.

I agree with the previous poster on the tranny rebuild. What was wrong with
the tranny that it needed a complete rebuild? A rebuild on the tranny should
have included a new torque converter. If you've lost fluid out of the pan on
a rebuild, I'd very much be questioning the competency of the shop that you
had do the work. And didn't your troop come with a 10 year, 100000 mile
warranty? I concur, you need to first check the reason for the leak,
determine if the tranny is developing the proper pressure (which a good shop
can measure for you) and tell you whether or not your TC is actually
defective, but I suspect it's not. I do think you may have been taken for a
ride in your tranny "rebuild".
Let us know how many miles are on your truck, and the results of a vacuum
gauge reading at idle when you start it (taken from a good vacuum source,
like the pvc hose inlet to the intake manifold. Should be pretty high if you
don't have a leak.
HTH,
GreenGas

Many thanks.  In the last few weeks I've changed the plugs, egr valve,
fuel pressure regulator, fuel filter, & the pcv valve.  They did a
scan and said that one of the plugs isn't firing.  Not sure why.  That
and an egr problem came up.  They've cleared it out and we'll see if
it returns.  
~GJ~

I feel for you, hang in there. Am hoping for your sake it's simply the low fluid that
aggravated it and the shop will have to fix it.
Once it's back in your hands, start systematically from the fuel pressure (filter),
injectors, spark plugs, idle air control and throttle position sensors

those are on my top-10 list of things to always check first and are all cheap to
replace

while there, also check the EGR valve condition (part cost: $230) and if a lot of
carbon build-up, clean it out

Insurance only covers towing if a claim is filed against the
insurance.  I climbed under the thing this morning and noticed a bolt
missing off the transmission pan and it looked like fluid had been
leaking from there, which explains a lot.  I still had to spend $80 on
the tow though.  And when/if this gets fixed I'll still have to figure
out why it won't hold an idle.  All this while battling a bankruptcy.
These are trying times indeed.
~GJ~

too bad you're not anywhere near s.florida - I would buy the car from you

don't give up yet, it's usually something very simple, in the case of the
transmission, it can be something as simple as a harness that has shaken
loose or very low fluid levels. sometimes simply resetting the computer
(disconnect battery) does wonders. am assuming you have access to a code
reader? autozone?

as for towing, your car insurance policy would normally cover a simple tow,
under 100 miles

please post back on your status

They will, I assume, honor their warranty.  However I have to be the
one to tow it there, 3 counties away.  And of course it's not a
priority as they've already been paid.  This was a (supposedly)
complete rebuild.  Included a new wiring harness.  Between this and
the oil guzzling engine I REALLY regret buying this vehicle.  I blame
myself as I didn't do the proper research beforehand.
~GJ~

now this is most unfortunate. does the shop honor a warranty on the rebuild? it should
if they are part of the national assoc for tran rebuilders.

just for comparison sake, I know this may not help you but for future reference for
archives, a totally rebuilt trooper transmission from the most reputable place (they
build 600+ units a month) in the USA costs just $1700 plus core deposit of $300-400
which is refunded once you ship back your old transmission. this rebuild is a complete
job where all internal parts are replaced, not just the worn or suspicious ones.

many local transmission shops take shortcuts but charge as if a full rebuild was
performed.

even on ebay (which I would not do..) the units run about $1100

Thanks for the posts.  Unfortunately the transmission, which I just
spent over $2000 to have rebuilt, has completely died again.  It won't
budge an inch.  Assuming I don't take a sledgehammer to it in the next
few days, I'll try your recommendations.  Many thanks.
~GJ~

I read all your previous comments and did not detect if you had the computer codes
pulled? Any Autozone will do it for free, worst case a small shop with an OBD-I reader
would charge 50-75 bucks and get them for you.

my other suggestion would be to purchase from Napa or Autozone (avoid other parts
dealers) the most expensive Idle Air Control sensor and Throttle Position Sensor, cost
for both parts would be around 100, in total. Can't hurt either way.

finally, if you read my note and the link posted, you may have a faulty ground and
could use any generic advise to install a ground wire between transmission and engine
or transmission and body (or do both, no harm either way)

I'm suspecting the problem now with this POS is the torque converter.
I've just paid 2K for a new transmission, replaced the egr valve,
plugs, pcv valve, fuel pressure regulator, and all filters.  It still
feels like the brakes on when I drive, especially uphill and a
whistling vacuum of air is heard when I first crank it up.  Out of
desperation I was about to try to replace the air intake manifold
gasket but someone riding with me today said it seemed like the torque
converter.  Any knowledgeable thoughts anyone?  This trooper is
ruining my life!

Oh-2001 trooper 3.5 4x4
~GJ~