There is talk about how reliability is bad on VW's.
Here is the deal folks. I own and love my 2000 Passat GLS 1.8 Turbo, 5-speed, 167,000 miles. It doesn't burn oil, and gets 30-32 miles per gallon, and is my daily commuter. I was a mechanic at a Volkswagen shop for 8 years. I have seen these problems come up in the past. Catalytic converters, lean air/fuel mixture, oxygen sensors, misfiring spark plugs and vacuum leaks. All of these can and will set off the Emissions Workshop warning alarm.
Lets start off with the cats, the cats utilize a lot of heat. There are screens and other highly engineered (and sometimes over engineered) components to them. No moving parts, but basically a system that each component plays a part in reducing emissions.
Here is the problem. Most of us are in a hurry to get here and there. Drive fast, find a parking spot, shut off the engine and run inside. Mean time, when you are in Starbucks getting your double decaf, triple skim, diet latte, the turbo and cats are still very hot and basically cooking. There is now no exhaust flow to remove the heat from the exhaust system. If you were to let the engine run for 2 minutes after getting to your parking space, exhaust temperatures would drop to a little over 300ºF instead of cooking between 900º-1000ºF. This will save the turbo ($1800.00), exhaust pipes ($400.00), cats ($2000.00), oxygen sensors ($500.00), and muffler ($300.00). Isn't this worth 2 minutes of your time. If you are in that big of a hurry, leave 5 minutes early! That covers the melting components.
Lean or rich air/fuel mixture. Several systems control this. Coolant temperature, intake air temp, barometric pressure, throttle position, fuel regulator, fuel pressure and oxygen sensors etc... the list goes on.
Here is my input. Everyone hates paying for gas these days. And we all look for the cheapest place to get gas. No problem. Look at the gas station, if it is a pig sty and no one there cares except to take your money, maintenance on tanks and filters there may be suffering. What I am talking about is how clean is the gas that you are putting into your tank?
When you are at the pump spending your 2nd childs tuition for college, look around. Look at the spin-on filter on the side or top of the pump. There should be a date on it. If the date is 6 months ago or looks like it was installed during WW2, I wouldn't get gas from that pump. Fuel comes in bulk to all stations. Do you think the fella filling the tanker looks inside it before he fills it each time? I don't think so. That filter on the side of the pump and the one under your car is your only defense in keeping the gas clean in your fuel system. You can add fuel injection cleaner, or mileage improvers. Some really do work, but in my opinion, if the filters are changed at the station and in your car correctly, you shouldn't need anything else.
Moral; change your filters. And not with the Kmart blue light specials either. A $4.00 filter is not the same as a $20.00 filter folks. Stay with OEM brands on any car. The car maker has engineers spec out what they want from its supplier. Time and money was spent on figuring that out. Stick with OEM parts.
Vacuum leaks. Hoses get old, brittle and eventually fail. This is normal. There is a lot of heat under the hood, and it effects the plastic, rubber and other high dollar components under there. VW has cloth wrapped rubber hose for vacuum lines. Simply, look under the hood, and follow those lines. If it is up against something metal, wrapped around the dip stick 3 times, or looks kinda hairy it is going to fail. Buy the cloth wrapped rubber hose, not the $0.29 plain rubber stuff from the local cheap auto parts store.
Another tip for those people that like to take their cars to the local self serve car wash, and pop the hood to give the engine a high pressure blast; that cuts old vacuum lines in a heartbeat. And guess what, ding, ding "Emissions Workshop".
Spark plugs and other assorted tune-up items. These items wear out. Check them and change them as needed. With OEM parts! I don't care about the latest and greatest 17 electrode quad band, mileage saver, junk item on late night TV. It is all junk and a waste of money. Back to the engineering, this has already been figured out for you. I don't care what kind of car you have, keep OEM parts in it. You paid for that technology. Do you think the 18 year old, rocket scientist behind the parts counter asking you if you want paper or plastic for your car parts knows better? I think not.
To sum all this up, if you want to have a reliable car, take care of it. Keep up on its maintenance, and it will take care of you. Parts do fail and can sometimes cause major damage. It is a mechanical or electrical part, and it can fail. Yeah, money is tight, but would you like to spend $200.00 on a quality tune-up or maintenance item or $4000.00 later on an engine?
Don't be afraid to look under the hood. It is your car, look at it. If you see something leaking, that is not normal. If something smells funny, or is making a different noise than normal, ask your mechanic, dealer or even read a book like the owners manual. There is no such thing as a stupid question. Either you know it or you don't. Your mechanic should be happy to answer your question. But respect his time too. Everyone is different and not everyone is car smart.
Oh, BTW, when the "idiot" light on the dash tells you to stop the engine because there is no oil pressure, you might want to listen to the idiot, he knows more than you at that point.
One of two things is happening. Either there is a faulty sensor saying something is wrong when there isn't, or there is a correctly working sensor informing you that there is in fact a real problem. Either way, pull over and check.
Just my input folks. You are the ones making the decisions.