Strange problem with my T4 van
VW Transporter IV Minibuss (70B, 70C, 7DB, 7DK, 70J, 70K, 7DC, 7DJ)

Hi!

I need tips and advice for a strange problem with my VW T4, 2002 (Petrol, 2,5L, AVT2,5)

The van always starts without problem and drives smoothly with easy throttle, but when i go “pedal to the metal” or throttle at a hill do the van start to run rough. Sometimes the feeling is similar to when it start to run out of fuel (fuel level is not the problem, just to describe the feeling). Got engine light on dash.

When i erase all faulty codes and makes a new reading do it not find anything and the engine light turns off. I can drive around the neighborhood and turn off/start the van without getting the engine light. But the engine light turns on when i throttle at a hill on the highway. Sometimes during the winter has the engine light turned off while driving, but has turned on again when i throttle “to much” in a hill.

If i read the codes directly after the engine light turns on again do it say “missfire on cylinder 3”.

Replaced parts:

– Fuel filter

– Spark plugs (Using NGK)

– Distributor cap

– Air flow sensor

Strange thing is that the problem got better after those parts were changed. But it’s not fully good.

No difference between full and almost empty tank. Do also not find any difference between cold and warm engine.

The problem started in september last year (7 mounth ago) and I’ve been using the van almost everyday since then. So I don´t think that there is a part as soon will break. Then it should done so at this point.

Any ideas?