I'm thinking the engine is sucking in air right where the coolant is leaking out; hence, your vacuum leak. I would change out both the LIM and the UIM gaskets at the same time. Make sure who ever changes out the gaskets doesn't forget to drain the radiator first. Doah!

jr'* 3800, what is this elbow that you are referring to? :?

Great observation! Yes, the rough idle became more evident during the same miles that the coolant loss began to occur (the last 6k miles) - which is why I have that bad feeling about driving it. My local mechanic-guy Randy (actually, I think he'* an engineer for GM by day) said that the rough idle was likely being caused by the plentum (sp?) - another common failure for these engines. I'm taking the car over to him tonight. He knew the symtoms of my car before I even described them. Getting parts from my brother - works for a parts distributor (can you say discount?).

So...will change both UIM and LIM, plentum, thermostat, possibly the hoses depending upon their condition, will clean the MAF and throttle bottle too.

Comment made at the end of the conversation - "...well Tracy, you certainly know a lot about your car!" My comment was "...thanks to the BC Club!" Kudos to the club once again. This time last year I had no clue what a UIM or LIM was. If it were not for this club, I never would have noticed the coolant loss and likey would have run her till she puked.

Tra cy....great news.

BTW..UIM = Plenum in his terms.
Make sure when the lower intake gaskets are picked up that they are the new style aluminum frame... (easy to tell..old are black frame, new are silver)

Tracy this club has been a godsend for all of us.Looks like your getting somewhere.

Lesson of the Day... thanks! Too bad I didn't read this before talking to my bro when checking on parts.

QUESTIONS:
1) I want the entire Intake Manifold Kit - right? It includes:
Intake Gasket, throttlebody gasket, pcv valve, retianer, and o-ring, Vacuum Tee & O-ring. ....what is a vacuum Tee??? http://www.dormanproducts.com/cgi-bi...rid=0x001d9fda
There'* no pics of the gasket...but a description of the above kit from my bro was "reinforced in failure prone areas."

OR...do I only want to buy the gasket kits?

2) If I get the about kit, do I need to buy the Plenum (UIM gasket) separate? Or should it be included in the above mentioned kit? I don't see it listed in the description.

3) What about that elbow thingy.... what' * the name: intake elbow? Or would that be the vacuum tee thingamajig?

4) Coolant: Go with Prestone'* Universal instead of DexCool?

5) EGR issue: I gather that the reason for continued failures is that the heat from the EGR warps the gasket. Does the newer designed kit (#1 above) correct this issue? Or should I be looking to replace the EGR too? I ask because it looks like the manifold has already been replaced once.

Granted...I'm assuming Randy will know what he is talking about - but I like to know beforehand based upon yous-guys' experiences.

1, yes taht looks like the right one... Should come with all gaskets necessary to replace the UIM. (I've always ended up with a few spare plastic pieces when I do an UIM. not really sure where they go.

2. should come with the UIM

3 elbow is between LIM and the acc bracket. if you plan to replace the LIM gaskets also (take off the LIM, then you will need a new one (GM dealer is easiest place to get one)

4 as long as it is dexcool. (it can be made by prestone) you should be fine.

5 I haven't read the thrtead so idk what has been discussed about hte EGR, but you should not have to replace the actual valve unless its bad. (which would throw a CEL)

Dropped her off at Randy'* tonight...holy HUGE garage! It was bigger than the house (a ranch) and had lifts and everything! I'm thinking we need to befriend this guy so we can use his garage for mini-meet mods sometime.

So...he listens to the car run and says, "..that'* not a vacuum leak...that'* a misfire". Great... I gave him the lowdown on the maintenance I've done, he'll check her out tomorrow night and let me know what he thinks. He agreed w/Boosty (I think it was Boosty) that the area I found the oil & coolant looking substance was not a normal place for coolant to be... there was more wetness there - and I've only driven it the 20 mins it takes to get to his house.... stay tuned....

She'* baaaaaccckk!!!

Rough Idle - cracked spark plug on #6. Ditchboy had trouble with that one...must have cracked it when installing it (back end - tough to get at). Stores were closed when this was found...moved plug to #3 spot - no missing at this time. Will replace asap.

Coolant Leak - LIM was cracked in three places. The UIM was very thin in a few spots as well. Luckily, the coolant leaked out up through the bolt where I could spot it.

Replaced at 59k miles:
LIM kit
UIM (aka Plenum!) gasket
OIl change (drats...too bad I just did it 600 miles ago. )

Preventative Maintenance:
Replaced Thermostat, Serpentine Belt, Top Radiator Hose
Cleaned TB and MAF

Glad to hear it all went smooth. Good job with the extra PM stuff too. That should keep you running for a while.