The Infamous: QUAD PORT.
Pre 1995 Intake manifolds, with full intake cast in EGR paths: ( Bless you MIKE for your quasi xray views ! )
If one or more ports are blocked and not 4 blocked, the remaining cylinders will misfire badly and make you very crazy.
This is the Major Bummer manifold.
Typically on all 16v motors, mid year 1995 changed to MONOPORT, at most factories.
Test this theory of misfire by defeating the EGR main and see if your misfire goes away.
Vin S6400124~ and S4192048~ (S= VIN year 95) There are exceptions, we see 96 X90's with 95 Intakes, sigh!
One cold drill out the welsh plugs and put new ones back.
We attack these 4 small EGR injectors, in the head port sides. (not fuel injectors) the EGR parts.
Finding can be hard if packed up. Use and ice pick or the like (a coat hanger , cut and sharpened?)
All photos by MIKE ! Xray view, 1:
How small those hole are , I don't know, but i'd want to find out so I can ream them, easy.
xray 2.
Below:
See pink arrow on the left, that is pointing to 1 , quad port EGR injector nozzle. Red below is FUEL.
The right pink arrow is the loves to clog "S" bend tube in side.
I have no experience cleaning it, but have photo's of others doing this.
Those inside intake runner orifices have got to be a bummer. A Major Bummer. I served under him.
All I can say is , "OUCH" !
The above intake manifold , was retired, mid year 1995 (1995.5) and the new OBD2 Mono-port, manifold, is then used.
ver 2, 11/2010 ,