5.0 and 5.7 Discussion, 1992 d'Elegance 5.7 liter coolant smell in Cadillac Engine Technical Discussion; So my brother just picked up a '92 Brougham d'Elegance with the 5.7 TBI motor.
It has 130K miles.
A friend of mine had a similar situation on a 96 Burb 454. It was the weep hole on the water pump. It would leak and smell, but evaporate before it had enough to hit the ground. Got up underneath to finally find.
My LT1 had a pin hole leak in the line from the coolant reservoir to the TB that sprayed a super fine spray that was very hard to see.
Caps can do it also, look for it leaking.
But my bet is on the water pump.... (sorry! I have seen it too much....)
Once you have the intake off, gasket match it will always guaranty designed/intended performance.
If you can find them, the TorquePlus intake gaskets can help for carb cars, probably for TBI too by breaking up the fuel better before it hits the cyl port. Some think it doesn't work, yes, it does, my 455 responded nicely to it (make sure no sharp edged in the ports, else the screen will be cut and can be injested...) Cold weather and low rpm drivablility was noteably improved. All carb guys I highly recommend. TBI cars may not improve much, but likely will improve some. High rpm operation might suffer slightly, but not until over 5000 rpm. Which these cars likely never will see anyway. But cold and low rpm (and mpg) did improve.