Update: I finally replace my intake gaskets 2 days ago. Unfortunately, the idle isn't back to normal yet. It is back down to around 1800-2200, which is a HUGE improvement over the 3200 which gives you bone shattering shifts into gear.

I may have damaged the new gaskets upon installation, but so far I haven't been able to confirm a new leak. I could see where the previous leak was upon dissassembly on the back right side. When I was putting the new gaskets on I found out where I may have messes on originally and caused this leak. (It took a couple of years before it happened.)

Be very careful once you set the manifold (common chamber) back into place. The fuel line bracket that bolt to the backside of the intake is a PITA. I was only able to unbold it after lifting the intake up & pulling forward a little. ...problem is, this is the same way I reattached it. I realized after it was too late that while i was bolting this bracket back into place & re-attaching the fuel return line on the left side, that I was letting the right side of the intake rest on the new gasket. When I realized this, I felt the gasket surface & could detect a slight depression or dent.

So now that my idle is still higher than it ought to be - I'm not sure if I need to replace the gaskets again (being more careful this time), or if it's something else. Using carb cleaner, I'm not able to find any new leaks, but you can really only check the outside edges of the intake manifold sealing surfaces. I'm wondering if I have a leak in the inner surface, but I can't get to it to check.

I hate to start replacing random parts as mentioned above, but I also hate to blow another $40 & 6 hours to replace the gaskets again... God, it sucks when your truck doesn't run right!!

I also need to find a replacement muffler, but it seems that there are none available, other than a universal or OEM...

Any suggestions welcomed!