I know this has been highly covered, but have not found many results specific for this. So thought I would drop an note here .......

Vehicle: 1996 S10 Blazer 4.3l vin W
4L60E trans

Whats been done so far:
New:
Plugs
wires
cap
rotor
Intake (upper and lower)
reman of the spyder
Vaccum lines
Fuel Pump
Fuel filter
TPS
FPR
Temp sensor
T-Stat
Radiator
Transmission
Cat Converter
Exhaust (from cat to tail)
O2 sensors

Cleaned:
EGR
MAF

Getting P304 and sometimes P0300
compression test on cyl 4 shows within limits (on the high end)
Leak down shows normal
Spark is good

So thinking about my best bet to fix this would be to convert it to a CMPI setup over the CPI

Any advice would be wonderful
Thanks in advance
Mark

INNOVA code reader model 1403 OBD I and II

Freeze Frame data:
Fuel 1 CL
Fuel 2 CL
Calc Load % 1.9
ECT 89
STFT B1 -4.6
LTFT B1 -7.0
STFT B2 -2.3
LTFT B2 -6.2
Map 35
RPM 581
Speed 0
MAF 4.10

Red LED

Emis blinking lights
Cat / EVA / C2S / EGR
flashing seems to be 3 then 6 guess for code 36 for Emission status

 

Think I answered my own q's on this one. Decided to go get some live data and recheck the Fuel Pressure under different stats.

Found the P0300 shows up faster under load then at idel
Fuel PSI is 65 at start of relay and sits at 60 when relay disenguages
Seen more then once that the Fuel PSI drops too fast, so did it at different intervals to make sure it was not a leaking popit
Same thing just different loss rates
No minor or strong change of Fuel PSI during running (load or idel) outside of normal specs
Checked intake for leaking FPR no leaks shown there

So means that I am looking at hopefully fixing the fuel issue when upgrading to the MPI, but not sure it will correct the P0300 code

New sign is ping under load meaning while in gear, but not present at idel only under load. Shows in both R and D, but not in P or N. Will show if you feather off and on the throttle but not constantly just off and on.

Not sure if this would mean timing kit or sensors, as the truck was running just fine for 8 months, then this just started out of the blue.

Will pull valve covers and check for bent rod on Cyl 4 as it was a P0304 code mainly with it switching to a P0300 off and on.