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Volkswagen bucking suddenly

I’m a broke grad student with a 1995 Jetta. I’ve had it about four years, and it’s mostly been all right. Granted, it’s mostly held together with luck at this point–my dad’s a former mechanic, and he did a fair bit of work on it before I moved a thousand miles away. The other day on my way to work, the car started bucking and shuddering, especially when I first started moving. I was very nearly out of gas, and I thought that might be the problem. I put some in and things got almost totally better almost immediately. Tonight, the car tries to start, but it won’t catch. My dad thinks I have water in my tank. Would that do this? And will Drygas really help?

While water contaminated gasoline is a possibility it’s also a remote on in my opinion. It does happen, but not to the extent of the complaints blamed on this.

There’s simply not enough info known so as to make much of a guess as to the cause of the no-start as it could be related to fuel, ignition spark, etc.

About all I can recommend is may getting a can of aerosol carburetor cleaner and shooting a healthy dose into the intake somewhere. See if the car will then start and run. If it does run for a few seconds before dying then you can assume it’s related to the fuel system although the fuel system can also be affected by things related to the ignition.
This won’t fix anything but can possibly let you know if the fuel pump has decided to go belly up.

Water in the tank is possible, but not likely. Ethanol in the gas tends to do the same thing as “dry gas” so more dry gas won’t help. It is more likely you finished off your fuel filter by sucking up some gunk that settles in the bottom of a gas tank over time. With an older car like yours this is even more likely.

Get a new fuel filter installed. If that doesn’t help sometimes the fuel pump can be compromised by that same dirt. Hopefully a new filter is all you need.

VWs are known for fuel pump issues, so at this point it’s my guess that running the car almost out of gas, caused the fuel pump to over heat. It is now seized. It’s hard to guess with the info given, but that’s what I get from reading this. Also ok is right try some starting fluid down the intake to see if the car starts. That will give you a good idea if it’s the fuel system or not.

Your vintage Jetta is also known for having a faulty ignition coil that will cause this exact symptom. VW recalled and replaced many of these coils, but yours may not have been replaced…or may have failed again.

I would have a new coil installed first before you try anything else. The fact that the symptoms occurred with low gas, and that they suddenly disappeared with gas additive, may be just coincidence.

PS–while the car is not starting, you can crank it and check for spark. If no spark, almost guaranteed it’s a bad coil. If getting a spark, then the coil is temporarily OK, but remember the coil problem is a random intermittent loss of spark, and the spark may disappear again at any time and cause more “bucking” symptoms.