Here's some more, including all the useful ones from the link above, though that link is still worth checking out for the funny ones.
A3, A4, A5 – platform name for certain model years of Beetle, Golf, Jetta, Cabrio
ACC - Air Conditioning Compressor
ACEA - Association des Constructeurs Européens d' Automobiles(Euro Auto Manufacturers Assoc)
A/D - Analog to Digital
AF - AirFlow
AFU - All Fouled Up
AG - Attorney General
AGM - Absorbent Glass Mat battery
AHU,ALH - engine models for A3 and A4 respectively
ALA - Aftermarket Lubricant Additive
ANL - Argonne National Laboratory
API – American Petroleum Institute standard
ASC - Anti-Slip Control
ASTM - American Society for Testing and Materials
ATDC - After Top Dead Center
ATF - Automatic Transmission Fluid
B4, B5 – platform name for certain model years of Passat
B20 - mixture of 20% biodiesel, 80% regular diesel
bbl - Billion Barrels of oiL
b/c - BeCause
BD – BioDiesel
BF - Brake Fluid
BHp - Brake HorsePower
BMEP - Brake Mean Effective Pressure
BO - Boost Overshoot, Best Offer
BSFC - Brake Specific Fuel Consumption
BTDC - Before Top Dead Center
BTU - British Thermal Unit
BTW - By The Way
CA - Central America
CAA/AAA - Canadian/American Automobile Association
CAD - CAnadian Dollars
CAFE - Corporate Average Fuel Economy
CAN - Controller Area Network, CANadian
CARB - California Air Resources Board
Cat – Catalytic Converter
CB - Catalyst Based, Citizens Band, Cetane Boost
CC - Cruise Control
CCA - Cold Cranking Amperes
CCM - Central Convenience Module
CCV - CrankCase Ventilation
CDA - Carbon Dynamic Airbox
CDI - Commonrail Direct Injection
CDN - CanaDiaN
CEN - Comité Européen de Normalisation (Euro Committee for Standardization)
CF,CG,CH,CI-4 – API oil standards for compression ignition (diesel) engine
CFPP - Cold Flow Plugging Point
CGSB - Canadian General Standards Board
CGI - Compacted Graphite Iron
CI - Compression Ignition, Cetane Index
CKP - CranKshaft Position sensor
CLS - Certified Lubrication Specialist
CONUS - CONtinental United States
CPO - Certified Pre-Owned warranty
CRD - Common Rail Diesel
cSt - CentiSTokes (kinematic viscosity)
CV - Constant Velocity joint
D/A - Digital to Analog
DAFS - Do A Forum Search
DC - Direct Current
DEER - Diesel Engine Emissions Reduction (DOE conferences)
DFI - Digital Fuel Injection
DFA/DFS - Diesel Fuel Additive/Supplement
D/FW - Dallas / Fort Worth
DIN - Deutsches Institut für Normung standard
DIY - Do It Yourself
DMF - Dual Mass Flywheel
DOA - Dead On Arrival
DOE - Department Of Energy
DOHC - Dual OverHead Cam engine
DOT - Department of Transportation
DP - DownPipe, Dead Pedal
DPF - Diesel Particulate Filter
DRL - Daytime Running Light
DSG - Direct Shift Gearbox
DSP - Dynamic Shift Program, Digital Signal Processing
DTC - Diagnostic Trouble Code
Dyno - Dynamometer
EBA - Engine Braking Assist
EBC - Engine Braking Control
ECK - Engine Cover Kit
ECM - Engine Control Module
ECU – Electronic Control Unit
EDL - Electronic Differential Lock
EDR(EDC) - Elektronische Diesel Regelung(Electronic Diesel Control) fuel injection
2-EHN - 2-EthylHexyl Nitrate
EIA - Energy Information Administration
ELSA - Elektronisches Service-Auskunftssystem (Service info system)
EM - Electron Microscope, ElectroMagnetic
EPA - Environmental Protection Agency
EPROM - Erasable and Programmable Read Only Memory
ESP - Elektronisches StabilitätsProgramm (Electronic Stabilization)
ESS - Engine Speed Sensor
ET - EinpressTiefe (wheel offset)
ETA/ETD - Estimated Time of Arrival/Departure
ETKA - Elektronischer Teile Katalog (VW’s computerized parts catalog)
FAP - Foreign Auto Parts
FF - Fuel Filter
FFA - Free Fatty Acid
FFT - Fast Fourier Transform
FHA - Federal Highway Administration
FIE - Fuel Injection Equipment
FIP - Fuel Injection Pump
FIS - FahrzeugInformationsSystem
FMEP - Friction Mean Effective Pressure
FMIC - Front Mounted InterCooler
FS – For Sale
FSI - Fuel Stratified petrol direct Injection
FT - Fischer-Tropsch diesel, For Trade
FTC - Federal Trade Commission
FU - Foul Up
FWD - Front Wheel Drive
FWIW – For What It’s Worth
GB – Group Buy, Glove Box
GDI - Gasoline Direct Injection
GHG - GreenHouse Gas
G/J - Golf/Jetta
GL,GLS,GLX – VW trim lines
GmbH - Gesellschaft Mit Beschränkter Haftung (Ltd Liability Corp)
GPH - Gallons Per Hour
GPS – Global Positioning System
GSM – Global System for Mobile communications
GST - Goods and Services Tax
GTA - Greater Toronto Area
GTG – Get Together
GTL - Gas To Liquid diesel fuel
GVRD - Greater Vancouver Regional District
GVWR - Gross Vehicle Weight Rating
GWB - George W. Bush, George Washington Bridge
HB - HatchBack
HC - HydroCarbon
HD - Heavy Duty
HID - High Intensity Discharge bulbs
HOAT - Hybrid Organic Acid Technology coolant
HP - HorsePower
HSDI - High Speed Direct Injection
HTH - Hope This Helps
HTHS - High Temperature High Shear
HU - Head Unit
IANAL – I Am Not A Lawyer (disclaimer)
IASG - International Automotive Sector Group
ICC - Interstate Commerce Commission
ID - Inner Diameter
IDI - InDirect Injection (gas)
IEC - International Electrotechnical Commission
ILSAC - International Lubricant Standardization and Approval Committee
IM – Intake Manifold
I/M - Inspection and Maintenance
Immo - Immobilizer
IOW - In Other Words
IP - Injector Pump
IQ - Injected Quantity, In stock Quantity
ISO - International Organization for Standardization
ITT - Inlet Turbine Temperature
IVHS - Intelligent Vehicle Highway System
JIS - Japanese Industrial Standards
JSW - Jetta SportsWagon
JW - Jetta Wagon
KBB - Kelly Blue Book
LATCH - Lower Anchorage and Tether for CHildren
LED – Light Emitting Diode
LCD - Liquid Crystal Display
LD - Light Duty
LF - Left Front
LOL - Laugh Out Loud
LPG - Liquid Petroleum Gas
LSD - Limited Slip Differential
LTFT - Low Temperature Flow Test
Mag - Magnesium wheels or light
MBC - Manual Boost Controller
Mcdo - McDonald's
MFD - Multi Function Display
MkIV or Mk4 – Mark IV, usually refers to cars using the A4 platform
M/M - Magnuson-Moss Warranty Act
MO - Money Order, Missouri
MPG – Miles Per Gallon
MSDS – Material Safety Data Sheets
MSRP - Manufacturers Suggested Retail Price
MTL - Montréal
MUTCD - Manual on Uniform Traffic Control Devices
N75 - boost pressure control solenoid valve
NADA - National Automobile Dealers Association price guide
NAIAS - North American International Auto Show
NB – New Beetle
NBB - National Biodiesel Board
NE - New England
NHTSA - National Highway Traffic Safety Administration
NIB - Never Installed Before
NOx - Nitrogen Oxides
NOT - Normal Operating Temperature
NPT - National Pipe Thread
NVH - Noise, Vibration, Harshness
OBD - On Board Diagnostic
OBO - Or Best Offer
OCI - Oil Change Interval
OD - Outer Diameter
Odo - Odometer
OEM or simply OE – Original Equimpent Manufacturer
OMG - Oh My God
OP - Original Post/Poster
ORVR - On-board Refueling Vapor Recovery
OSAT - OutSide Air Temperature
OTOH - On The Other Hand
OTR - On The Road
PAO - PolyAlphaOlefin oils
PCB - Printed Circuit Board, PolyChlorinated Biphenyl
PDC - Park Distance Control, Parts Distribution Center
PDE - Pumpe-Düse Einspritzung
PDF - Portable Document Format
PDX – Portland, Oregon
PIN - Personal Identification Number
PIO - Poly Internal Olefin
PITA - Pain In The Arse
pls - please
PM - Particulate Matter, Private Message
P/N - Part Number
PNW – Pacific NorthWest
POS - Piece Of S***
PPP - Paie Pas Pantoute
PS - Power Steering, Post Script (also PowerService)
PSI - Pounds per Square Inch
PST - Provincial Sales Tax
PW - Power Windows
QA - Quantity Adjuster
RCA - Radio Corporation of America audio connector
R&D - Research and Development
RF - Right Front
RLR - Remote Lid Release
RME - Rapeseed oil Methyl Ester (biodiesel base)
RPM - Rotations Per Minute
RTFM/RTFQ - Read The Freaking Manual/Question
RWD - Rear Wheel Drive
SA - Société Anonyme (=incorporated), South America
SAE – Society of Automotive Engineers standard (usually “English” not metric measures)
SAPS - Sulfated Ash, Phosphorus, & Sulfur
SB - Smart Box
SCCA - Sports Car Club of America
SCR - Selective Catalytic Reduction
SDI - Suction Direct Injection
SEM - Scanning Electron Microscope
SFBA - San Francisco Bay Area
SG - Specific Gravity
SJ,SK,SL – API oil stardards for spark ignition engines (non-diesel)
SKC - Secret Key Code
SMD - Surface Mount Device, Specific Material Designation
SMF - Single Mass Flywheel
SMIC - Side Mount InterCooler
SO - Significant Other
SOHC - Single OverHead Cam engine
SOL - So Out of Luck
SPL - Sound Pressure Level
SRP - Stealth Race Pipe
SRS - Supplemental Restraint System (airbags)
STLE - Society of Tribologists and Lubrication Engineers
SULEV - Super Ultra Low Emission Vehicle
SUV - Sport Utility Vehicle
SVO - Straight Vegetable Oil
SW,s/w - ShortWave, SoftWare
T90 - Temperature at which 90% of fuel evaporates
TB – Timing Belt, Tuning Box, Throttle Body
TBA - To Be Announced
TBN – Total Base Number
TC - Torque Converter, Touring Class, Transport Canada
Tcf - Trillion Cubic Feet
TCM - Transmission Control Module
TDC - Top Dead Center
TFL - TagFahrLicht (DRL), Torch FlashLight
TIA - Thanks In Advance
TIP - Turbo Inlet Pipe
TIT - Turbine Inlet Temperature
TMC - Traffic Message Channel
TPS - Taxe sur les Produits et Services
TSB - Technical Service Bulletin
TT - an Audi model
TTY - Torque To Yield (stretch) bolts
TÜV - Technischer ÜberwachungsVerein standards lab
UCBO - UnConventional Base Oil
UFB - UnFreaking Believable
ULEV - Ultra Low Emission Vehicle
ULSD – Ultra Low Sulfur Diesel
UOA - Used Oil Analysis
USD - United States Dollars
VDS - Vehicle Description Section
VE - VertEiler (distributor) pump
VG - Variable Geometry
VHVI - Very High Viscosity Index
VIN - Vehicle Identification Number
VNT - Variable Nozzle Turbine
VOA - Virgin Oil Analysis
VOC - Volatile Organic Compounds
VRLA - Valve Regulated Lead Acid battery
VSS - Vehicle Speed Sensor
VTG - Variable Turbine Geometry
VWV - VolksWagen Vortex board
2WD/4WD - 2/4 Wheel Drive
WFC - Warp Field Collapse
WFO - Wide Freaking Open
WHp - Hydraulic HorsePower
WMI - World Manufacturers Identification
WOT – Wide Open Throttle
WP - Water Pump
WTB – Want To Buy
*** – What The F***
WTG - Way To Go
WVO - Waste Vegetable Oil
XHVI - eXtra High Viscosity Index
YMMV - Your Mileage May Vary
And then there’s abbreviations for members, such as
DD - dieseldorf
DG – DieselGeek (member name corrado tdi)
DBW – Drivbiwire
And company/product names:
ADC - Amsoil Diesel fuel additive Concentrate
ADM - Archer Daniels Midland
AMSOIL - AMatuzio Synthetic OIL
ARP - Automotive Racing Products
AST - Assenmacher Specialty Tools
ATE - Alfred Teves Erzeugnissen (brakes)
AVL - Anstalt für Verbrennungskraftmaschinen • List (Diesel engineering firm)
AZ – AutoZone
BP - British Petroleum
CAT – CATerpiller
C&D - Car & Driver magazine
CR - Consumer Reports
CT – Canadian Tire
D1 - Delvac 1
DK - PS DieselKleen
GCF - Gulf Coast Filter
GE - General Electric
GY - GoodYear
HF – Harbor Freight
H&R - Heine und Remmen springs
KK&K - Kühnle, Kopp, und Kausch turbos
K&N – Ken and Norm air filters
MB - Mercedes Benz
MOMO - Moretti-Monza cabin accessories
NS – Neuspeed
OAI - Oil Analyzers Incorporated
OMD - Oldman Modified Dawes boost controller
PB – Pierburg
PC – PetroCanada
PS - Power Service
QS - Quaker State
RC - Rocket Chip
RL - Red Line oil
SDP - Steyr-Daimler-Puch engines
STP - Scientifically Treated Petroleum
TA - Travelcenters of America
Up - Upsolute chip
VASB - Van Aaken Smart Box
VWC - Volkswagen Canada
VWoA – Volkswagen of America
Wett - Wetterauer chip
WRD - Watercooled Racing Development
I have two minor quibbles with FlyTDI Guy
PD – Pumpe Deuse
IMHO – In My Humble Opinion