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I have a manual 1982 diesel VW Vanagon with a 1996 Passat TDI engine in it. This morning (low 40s temp), accelerating up a hill, heard a hissing sound in left rear. Check tires, no problems. Able to start back up, change gears, but bad forward lurches past 15mph or so and can't get it going above 20-25mph.

I did just have a bunch of brake work done (new rear brake shoes, resurface brake drums, 2 new brake drums), but drove it for a few days no problems. It's been a little hard to start lately, taking a while to ignite.

Any thoughts appreciated.

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I would not think that the brake work is the problem but if you think there is a real possibility that it is, the let the person who done the repair work check it out. The engines performance depends on air, fuel, and mechanical condition all being present and correct. Any unsual or heavy noises from the engine? Check for disconnected or leaking air and vacuum hoses. Check the fuel filter, have you drained it out of any water content. Most fuel filters allow the water to be collected in it so you an drain it. In cold weather you can have the diesel freezing or at least icing up and blocking fuel flow. Last but not least fuel pressures. If everything else looks OK then your local repair shop will be needed to do a pressure check.

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Thanks, Allan. I ended up finding that the hose from the intercooler had come off. I clamped it back on and all was good. – bryanlandia Jan 4 '14 at 0:22

It sounds as if there are bubbles in the fuel. Check for bubbles in the fuel prefilter located between the tank and the pump.

This is a common occurance when the van has been fitted (possibly by a previous owner) with a replacement fuel tank that are built (internally) with a smaller diameter metal "pick-up" tube that is used to feed the fuel lines.

If this is the case, then somewhere between that metal tube and the fuel pump, you have the possibility of cavitation. This cavitation appears to be air bubbles, but the bubbles are in fact gasoline vapor, which in turn results in sparatic delivery and lurching and a dramatic loss of power.

There has also been cases seen where the fuel tanks have had a defective pickup tube (the metal pipe discussed earlier). These were known to crack causing air to enter the system when the fuel level was below the break.

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