[Waiting Falcon]

My problem is my 2006 VW tdi. After the fuel filter change, it started having momentary failures. RPMs would drop and immediately rise, it is happening in any gear, any speed.
To start with -this has been going on for about 10 days- it was barely "felt" yesterday at 15 mph in town it was a definitely hard jerk.

I do not want exploratory "surgery" on this car..I want answers. I need the car but I am having strong doubts especially when I need to make a 1000 mile business trip.

 

[Harry Chickpea]

What you want and what you get can be two different things.

A simple logic diagram would point to something happening during the replacement, re-visiting that looking for damaged wiring or crimped fuel lines and exchanging the filter for yet another one to rule it out.

 

[Darren]

Air in the fuel system? I changed the filter on a 6.9L once. The truck wouldn't start afterwards even with the filter filled with fuel. It turned out the lift pump arm had broken off, but the injection pump had the moxey to still suck fuel until the filter was changed and the vacuum was broken.

 

[Waiting Falcon]

Nearly everyone I talk to says fuel filter...I think that too. But without looking at it again, my mechanic thinks it is wiring?
Can you know it is or isn't the fuel filter without taking it off and examining it?

So far I have not had problems with starting...........

 

[farminghandyman]

most likely it has a computer, and I would suggest to take it some where and have the codes read, if you do not have a code reader.

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yes the fuel filter would be suspect since it was last touched. is the pump wiring running near the filter to the pump?

but IMO I would question if it is a filter problem, as to what would cause a monetary stoppage, a bout the only other thing is air in the line, but more modern cars have a return line as well, so the air should be pushed back to the tank, and the question is where is the air coming from,

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I would think a electrical problem would be more possibly suspect, I would think the codes would guide one.

 

[Waiting Falcon]

If he had it on the computer Tuesday.....it showed no codes....
I had no idea this car had so many computers but there is one for most things...

He said this model has wires that can crimp but he checked the wiring harnesses for fraying/crimping possible wire breakage.
Would the diagnostic show air in the fuel lines/filter?

 

[agmantoo]

I associate the problem you are experiencing from air being pulled (weeping) into the fuel system from a fitting/filter not being air tight. This typically occurs on the suction side of the fuel plumbing.

 

[nosqrls]

Did the o-ring on top of the filter move. On tdi's there is an o-ring that looks like the olympic symbol if it moves fuel will go back to the tank and the injection pump will suck air. also remember your lift pump does not start until the engine does. engine starts on fuel in filter. also check for water in filter remove screw on top and jumper lift pump. if air comes out bleed it or nothing you need a new lift pump.good flow filter maybe bad. wife drives 09 jetta tdi.

 

[GoldenCityMuse]

Sounds liek a problem when the filter was changed. That is your starting point.