Decoded the RPO codes:
AJ1: WINDOW TINTED DEEP, ALL EXCEPT W/S AND DRS
AM0: FLEXIBLE CONFIGURATION
ANL: PACKAGE AIR DEFL, FOG LP
AU3: CONTROL SIDE DR, ELEC
AV5: SEAT FRT BKT, HIGH BACK
AXP: NT POSITION, MULTI-PURPOSE VEHICLE
AX3: LOCK CONTROL, ENTRY REMOTE ENTRY - DEALER ACTIVATED
A31: POWER OPERATED, ALL DOORS
A78: ADJUSTER FRT ST BK MANUAL, DRIVER & PASS, RECLINING
B32: COVERING FRT FLOOR MATS, AUX
B33: COVERING REAR FLOOR MATS, AUX
B94: NTATION EXTR, EMBLEM, BODY, VAR 1
CTF: PACKAGE INTERIM CONTROL
C25: SYSTEM RR WINDOW, INTERMITTENT
C6J: GVW RATING 5,100 LBS
C60: HVAC SYSTEM AIR CONDITIONER FRT, MAN CONTROLS
DC4: MIRROR I/S R/V TILT, DUAL READING LAMPS
DH6: MIRROR I/S FRT VAN LH & RH, SUNSHADE, ILLUM
DK6: CONSOLE ROOF INTERIOR
D48: MIRROR O/S LH & RH, REMOTE CONTROL, ELECTRIC, COLOR.
D55: CONSOLE FRT COMPT, FLOOR
E55: BODY EQUIPMENT END GATE
FE9: CERTIFICATION EMISSION, FEDERAL
FF4: ARM LH TORS BAR SPRING ADJ (C)
FF5: ARM RH TORS BAR SPRING ADJ (D)
GMC: PLANT CODE PONTIAC, MI, USA
GT4: AXLE REAR 3.73 RATIO
G80: POSITRACTION LIMITED SLIP
JM3: BOOSTER BRAKE, 240MM TANDEM, HIGH FLOW
K34: E CONTROL AUTOMATIC, ELECTRONIC
L35: ENGINE GAS, 6 CYL, 4.3L, CPI, V6, 90 DEG, H/O
MX0: MERCHANDISED TRANS AUTO PROVISIONS, O/D
M30: TRANSMISSION AUTO 4 SPD, HMD, 4L60-E, ELECTRONIC
NF2: EMISSION SYSTEM FEDERAL, TIER 1
NQE: FUEL TANK 76L, 20 GAL, SINGLE
N33: STEERING COLUMN TILT TYPE
N40: STEERING POWER, NON-VARIABLE RATIO
N90: WHEEL 15 X 7, ALUMINUM CAST, 4.75 INCH BOLT CIRCLE
P16: CARRIER RR MOUNTED, SPARE TIRE
QFN: TIRE ALL P235/75R15-105S WL R/PE ST TL ALS
R7A: OL SALES ITEM NO. 26
R7B: OL SALES ITEM NO. 27
SLM: SALES PROCESSING STOCK ORDERS
UA1: BATTERY HIGH CAPACITY, WET
UP8: RADIO PROVISIONS, AM/FM STEREO, INSTRUMENTATION
UX1: RADIO AM STEREO/FM STEREO, SEEK/SCAN, AUTO REV MUSIC SEARCH CASS, EQUALIZER, CLOCK, ETR
UY7: WIRING HARNESS TRUCK TRAILER, HD
U52: CLUSTER INST, ELECTRONIC
U73: ANTENNA FIXED, RADIO
VR4: TRAILER HITCH WEIGHT DISTRIBUTING PLATFORM
VXS: LE COMPLETE
V54: LUGGAGE CARRIER ROOF, PAINTED
V73: VEHICLE STATEMENT USA/CANADA
WJ7: OVERRIDE INTERIOR *LEATHER* (TO BE USED BY ALL USERS BEGINNING 1997 MODEL YR)
XFN: TIRE FRONT P235/75R15-105S RWL R/PE ST TL ALS
YC3: CONVENIENCE PKG DECOR LEVEL #3
YD3: (BASE EQUIP) FOR SCHEDULING GVW PLATE
YD5: G FRONT BASE EQUIPMENT
YD6: G RR, BASE EQUIPMENT
YFN: TIRE REAR P235/75R15-105S RWL R/PE ST TL ALS
ZFN: TIRE SPARE P235/75R15-105S RWL R/PE ST TL ALS
ZM8: PACKAGE COMBINATION - ELECTRIC TAILGATE RELEASE/RR WINDOW DEFOGGER
ZQ2: PACKAGE DRIVER CONVENIENCE
ZQ3: PACKAGE DRIVER CONVENIENCE II
ZY1: COLOR COMBINATION SOLID
Z70: MARKET BRAND OLDSMOBILE
Z82: TRAILER PROVISIONS SPECIAL EQUIPMENT, H.D.
1SA: PACKAGE OPTION 01
1SZ: UNT OPTION PACKAGE
44U: PRIMARY COLOR EXTERIOR, REGATTA GREEN PEARLESCENT (02)
55A: STRIPE COLOR ACCENT, GOLD (96)
6CR: COMPONENT FRT LH COMPUTER SEL SUSP (6CR)
64I: INTERIOR TRIM LT REED (I) (05)64IINTERIOR TRIM LT BEIGE (I) (96)64IINTERIOR TRIM MED DK SABLE (00)64IINTERIOR TRIM DK SABLE (00)
642: TRIM COMBINATION LEATHER, LT BEIGE (2) (96)642TRIM COMBINATION LEATHER, MED DK SABLE (2) (00)642TRIM COMBINATION LEATHER, LIGHT SHALE (2) (02) (HOLDENS) 309
7CR: COMPONENT FRT RH COMPUTER SEL SUSP (7CR)

 

My brake pedal has been going straight to the floor. Everyone I've asked has said that if there aren't any fluid leaks, then the main cause for the brake pedal going to the floor is a bad master cylinder.

So, I replaced the master cylinder, and spent three hours and three quarts of brake fluid trying to bleed the air out of the lines. There is NO air coming out, but the pedal is still going straight to the floor. I'm beginning to regret buying this car.

 

I had that problem on my Ranchero. I replaced the booster and all was good

 

How are things with your Blazer?

 

Just got it back from the shop on Wednesday. They replaced the seals in the trans, new fuel pump, gas tank flushed out, transfer case rebuilt, oil and filter change as well. Just did a full interior detail on it, and going to get plates and registration on Tuesday. Need to get some tires, heater core and blower motor are shot. I'm really liking it so far

 

You may need to bleed the ABS system

 

All right...so, after spending hours and hours searching for a way to bleed the ABS unit without using a scan tool, I decided to take it to Brakes Plus to have that done. The brake pedal finally feels normal. I also had them do the alignment. The steering wheel still isn't straight, so I need to have them re-do it. But they charged me a total of $122 for everything. So, now the Bravada can share daily driver status with my 2017 Mazda3, which is good because it's supposed to snow tomorrow.

Next step: new tires and start sanding the rust on the roof.

 

I haven't posted a photo in a while, so I figured I'd post one today. It looks good in the snow:

 

After driving it in the snow and ice last Monday and Tuesday, the brake pedal started getting spongy again. It turns out there still had to have been air in the ABS unit that got cycled into the lines, so I bled the brakes at the wheels again, but no air came out.
Nobody in town has a scan tool for pre-OBDII vehicles to do the automated bleed procedure, so I don't know what else to do at this point.

 

Have you tried to activate the ABS to get it to cycle ? You have good conditions to do this with slippery roads, ice & snow. The first week I had mine I tested the ABS and blew the rear brake line. All is well after a replacement line was installed. I did not have to have the ABS bled at that time .
Reverse bleeding is the only method capable of bleeding tough ABS units without a scan tool.