SC Gasket and SES Light

Hey everybody. This is my first post of substance in the engine forum. I've got all the appearance mods done with the car and now I need to start moving on to performance and maintenance.

First, though, I've got to do some maintenance. Recently, my car has been idling roughly and I can hear the coupler in the SC rattling inconsistently (i.e. without its normal rhythm). This started occuring 2-3 weeks ago out of the blue. At first, I thought it may be a coupler issue. It is original and I know how worn out they can get, but I know that they don't usually cause any problems like the ones I'm experiencing unless they frag.

So, I took the thing in to my usual mechanic. Bear with me, too, becuase I don't have much experience with engine bay issues except from the info from this site. Anyway, I took the car in because the SES light was on. The code on their scanner read "Bank 1 Lean," so obviously it was some kind of a fuel issue. I always fuel up at the same station and I've even put regular gas in there and the SES light has never come on until a few days ago, so we popped the hood and realized the SC gasket was leaking, as well as the lower intake manifold gasket.

So I'll be headed back up there in about a week to work on it with them. I'll be replacing the coupler while I'm at it. I just wanted to share my experience with this so far, and to see if anybody has any advice for replacing these gaskets, purchasing them (haven't started searching) or doing the work. Thanks for reading!

You don't specify for which riviera it is. Since you said Bank 1 lean, I'm guessing it's the 98.
If you are going through that trouble, I would highly recommend getting the lower intake manifold gasket done at the same time.

Bank 1 lean doesn't necessarily affect your mileage. It can be an 02 sensor getting lazy. At 140k mi, if they are original, it's normal. If fixing the vacuum leak you described doesn't work, look into this.

I've had good luck buying gaskets from W-body store.

It's my 98. That's why I didn't post in the Series I forum. I was planning on doing both gaskets at once too and I'm almost certain the O2 sensors are original.

I'll look @ the W-body store when I have some time Monday, thanks for the tip!