I have searched around for most of these questions, and ended up with inconclusive answers and things that plain never were solved.

#1) My car has that seemingly common jerky acceleration especially up hills. It'* quite alarming really. All the posts I seen involving that were never solved. The poor guy changed 50% of his engine pieces to no avail, and since I already went through random diagnosis when my motor went bad, I figured i would ask one more time.

#2) my plenum has a small drip on the firewall side around the TPS and whatnot. The drip is external (it seems anyways (prays)), but my question is, what would a non properly seated plenum do to performance? I haven't had a chance to fix it since i don't have a garage at my disposal at the moment, and I am a little shy to open my motor up in the driveway like that.

#3) The car starts up well and drives amazingly well considering how rapidly the performance degrades as it heats up. I commute to work, and jumping on the highway right away shows this well.

#4) The plugs all look nice. Not burnt up or white or corroded. The plug wires are new as well as the plugs about 800 km ago.

#5) I feel the car is getting lack luster mileage, but i haven't gone as far as to try and measure MPG. My major preoccupation these days is trying to drive it nicely after it warms up since the jerking doesn't feel like its a good thing to be happening. My last car did something similar, and soon after tossed an arm through my oil gallery

I don't believe I have a vacuum leak, unless the plenum is doing something crappy in those regards. All I know for sure is I would love to see this car running properly, even just once......... lol. It'* be nothing but endless hassle for over 6 months. My $1150.00 Bonne is now balls deep into me for about $3200.00. It was one of those I'll try one more thing, ok one more thing, once more. Then before you know it the car is (worth) more than its worth.
My uncle bought a slightly older car with the 3.8 in it. he revved it up, and it sounded ballsy as hell, tons of power to spare. Its a shame cars cant donate, because I have a terminally ill patient.

Thanks in advance to whoever can throw in ideas for whatever they can. Welcome to my nightmare

No one has anything to chime in about on anything i asked up there. Did i not ask in a proper fashion. I assumed it would be better to ask my questions all in one place, than it would be to make separate posts. I have tested about everything I know how to, and I just want this rotten car fixed. Forum searches haven't helped me much, and neither has goggling for answers. I have a feeling its one stupid thing causing all my problems, and i just don't know what it might be. Thanks to the 9 people who at least read this.
Peace

hi

1: have you check coils? and plugs/wires all good? if not, could be transmission related

2: if it is leaking externally, thats better, but it still needs to be addressed. the upper could be a sign of rupturing or the gasket is due for replacement....

3: cars run liek rapped ape when cold, yes.....but its not good to be racing around when their cold...it coudl be time for a full tuneup....

4: do you have any ways to hook up your car to a scanner that reads rela time data, to check Fuel trims to check for a leak....

let us know

The plugs and wires are new, they are all burnt nicely (nothing seems wrong with color/condition) So i assume they are running well. The coils all test in acceptable ranges, but I never tested the lower connections to them when they were changed.
I will fix the plenum leak when i get a garage so crap doesn't fly into my motor outside, as i assume that wouldn't be very good. I have a spare gasket for it.
It runs nice when cold, but I'm not "racing around". Its just noticeably more responsive, and has better acceleration.
The guy at the GM dealership here said he would scan my car free, but work hours are keeping me from having it done. Either he is busy at the time or I am. We are working on it though.
I have no engine light coming on.
I did have the UIM failure by the stove pipe, and ended up losing that engine. Now its replaced with a Newer motor, that was completely once overed before i bought it. It has all new gaskets everywhere. any seal that could have been changed was, or so they said. Every one that'* visible looked new to me.
I never changed my 02 sensor after all the anti freeze fiasco, and have read that anti freeze is like a death sentence for them. When a car has its O2 sensor unplugged, should it run differently. Mine didn't. I have the O2 sensor from the new motor, but the electrical plug was different. if its the same, can the plug be switched?

Oh and one more thing:
When I take this plenum off again, How do I get the old stove pipe out! We got the reduced diameter pipe in the new plenum, but at first didn't know what it was. Then once we found out, were scared to get the old pipe out. Its really in there!

you should not have to worry about the stovepipe, which UIM do you have in there?

I'm not sure of the model # or anything like that. Its the big plastic plenum like this one http://app.infopia.com/img/image/fp/.../img-2/img.jpg . I cant promise its the exact same one, but it appears to be.
That stove pipe is where my initial failure was, and it cost me a motor and a lot of time and money. I want to put that reduced stovepipe in so this wont happen again, or at least seriously prolong its life.
I put a motor in with like 70,000 kms that was completely checked over and redone (boy did that cost me), and i am hoping that this car will last a good little while now. But this problem was there after pissing around with the prior motor (R.I.P), so i know it isn't this motor, it is something that stayed with the car.
I have tested coils, TPS, checked for vacuum leaks, and found nothing wrong after replacing one vac boot that made no change. The fuel filter was also recently changed.
One question I do have about vacuum lines on this car is, where the line goes to the tranny, there is a little joiner that seems to limit vacuum in one direction type thing. I have been wondering if that is malfunctioning, and more so, if it can be removed. anyone know what this is for/why its there?
When I bought this car, it ran like a top for about a week. That is until that small leak turned into a huge one. Its been a nightmare ever since.

i was asking if you went with a dorman or APN kit for your UIM....

yes the stovepipe is the other known failure point as well as the LIM gaskets...

thats a tranny vacuum line since your trans is vacuum operated

I am not even sure what the brand of the plenum is. I just went to check it to see if maybe it was stamped with some ID, but its all just numbers etc.
I know the line is vacuum, but it has a small fitting about 3 inches before it goes to the tranny. It goes hard line, tubing over it, to a small fitting that looks like this --|-- and then more tube to the tranny. My question is what is that --|-- fitting. It seems to let more air through one way than it does the other. Does it need to be there, or was it added in. If its added or needed can it fail. If it does fail, might it cause these types of highway stuttering or chuggling as it seems to be called. I want to know if i can remove it, and run a line directly to the tranny, at least just to check, its easy to remove and all that, but i dint know what the consequences may be.

im unsure, transmission'* are not my strong point