When you did the compression test, did you let it keep cranking till you noticed the gauge stopped gaining pressure, and was the motor slightly warm?
When I did my first compression test I did this, and got low numbers, went back and did it the right way and got much better numbers.
With those numbers only one cylinder is good, cylinder 1, the rest are low enough to cause misfires, with those numbers any cylinder below 119.5 can cause a misfire in that bank.


Here is a good thread to help with compression testing.
Part 1 -How to do an Engine Compression Test (GM 3.8L)

Another reason for the compression test is number consistency. If you have low compression in 2 adjacent cylinders, there is the possibility of head gasket failure. We still only have half the numbers though...

Found out why the compression is so low. Weak battery. Tried it this morning after charging all night and #3 reads 120.

Quick question. Anybody tried the doorman intake manifold #615179 on a 92 engine? their website and rock say it doesn't fit on a 92. only 93-95.

William, also the only way to get the engine hot is to set it on fire.

92 used an aluminum upper with no egr. I made up a list on mine when i did it july 2012. Mine isnt showing any signs of letting up so far

Your signature says the car is a '93, is the car a '93 or a '92 like just mentioned?
Is the UIM plastic or aluminum?

If it is a '93 you should be able to use that UIM, not if it is a '92 though.
I do see a plastic DELPHI Part # FH10112 listed for the '92 on rockauto, but that is probably meant for a '93, sometimes rockauto can have incorrect part listings.

My apologies, I had a typo in the signature. It is a 92. I have corrected the issue.

Are the aluminum plenums known to warp?

Interesting the FH10112 fits 91-95 but the dorman says 93-95 (on their website)

use a block tester to test for exhaust contamination in coolant. or try a compression test. smell for sweetness at the exhaust pipe.

Ahh ok, thanks for fixing that.
I have not heard of the aluminum UIM'* warping, they should hold up a lot better than the plastic ones,if the UIM Gasket is damaged I'd replace that though.

I'd trust what Dorman says over Rockauto, they most likely had that plastic UIM listed wrong, it would not be the first time.

Ugh, that changes everything.

The aluminum units don't normally warp, but they have been known to dump coolant in to one cylinder if the seal between the UIM and LIM fails.

What have you found out so far? Where is it leaking from? What happens if you try and run the engine?

Unfortunately between the weather, and my time, All I've had a chance to do is check the first bank of cylinders for compression. I do see that the UIM gasket failed and sprayed coolant all over the exhaust manifold.

I didn't try running her again after I got her home and all the plugs are out for the compression test.

That'* all I can say for now. Hopefully I'll be able to give everybody a better update on Friday.