1999 4.3 Cpi

Started doing a intake manifold job on my 1999 4.3 (w) Blazer. When i removed my upper plenum there was washing of my intake manifold in the rear and left rear side. I search for a thread on this, but nothing was found. If it is the cpi unit can you buy the whole unit with injectors for replacement. I just found seperate injector online. Thanks for any help you give me.

Was you getting coolant in the oil or had a coolant leak in that area?
It is unusual for that injector setup to leak inside.
But possable for the injector O ring to leak out bottom or top of injector body.
Does the fuel pressure have a fast leak down?
They are separate replaceable injectors in a injector body.
With intake off hook your fuel line back up.
Disable spark and ign and flip key on and crank up fuel pressure and look for leaks around injector body.
Also you can pinch/block off return line and get full pressure and check for leaks.
Then with ign and coil disabled crank engine and watch injector lines for leaks.

There is a newer setup called MFI and install was covered in "How To/Tech" section - it replaces the entire main body and poppets and moves the pulse control outboard to the poppet end and includes a new regulator all for about $250 but you will have to check todays prices.

What are the actual benefits of doing this? Going with MFI I mean