Hi,
My 94 Bravada has a strange (to me) problem. A month or so ago, the PCM
indicated code 32 - EGR valve.  The idle was uneven and the car would
sometimes stall when stopped.  I tested the EGR valve, the position
sensor resistance was slightly out of spec when the valve was closed, so
I replaced it.  The code went away and the car ran fine after that.  
Then, a couple of weeks later, it suddenly it started running extremely
rough on idle.  Much worse than before.  No check engine light.  Low
vacuum, no brake boost.  I suspected the booster was leaking.  I
disconnected the vacuum hose and plugged it. Still very rough idle,
smoothes out at higher RPM.  Next, I put a scope on the injector leads
and measured current. I saw the normal injector pulses running at the
same rate as the ignition, but also saw random narrow pulses between the
normal pulses.  Any ideas what is going on?  Is this a PCM problem?  The
ignition looks good, no extra pulses there.  The injector assy was
replaced under warranty a couple of years ago due to a leaking
regulator.  The fuel pressure measures good and holds after the engine
is turned off, so the reg must still be good.

Thanks,

-- cb