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Hi,

I'm trying to help a friend out who's got problems with his petrol T4.

When the engine is idling, there is a hiccup every 10 seconds or so.

When the engine is warm and under load, it looses power. You can feel the power dropping away, the more you press the accelerator, the worse it gets. If you dip the clutch and rev the engine, it revs fine, but release the clutch to pull away and the engine judders and tries to stall.

The MAF sensor was initially thought to be a problem, but the ECU has been sent off for testing and everything has come back fine. The fuel filter has been replaced. The temp sensors have been replaced. The hoses from the inlet manifold to the ECU have been replaced. We've taken the throttle body and the ICV off and cleaned them out. That hasn't made any difference.

It's all clean inside the inlet manifold too.

I'm stuck and don't know what to check next. Any suggestions?
 

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Coil would be my next port of call.

I had a coil fail on me and gave some really weird and intermittent problems. One minute fine the next minute the engine would lose all power and die before springing back into life.
 

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T4 2 Ltr AAC one of the first RHD off the production line 1991
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A lot of familiar symptoms there, love my T4 AAC but it's [email protected]@dy frustrating.

You have checked the obvious, so as noo noo says coil worth a check

On the fuel side, I had exactly the same symptoms with one fault (not the pulsing though still can't sort that, see my other threads), the van would stall and then restart but no power, disconnect the TPS and see if it makes a difference. The TPS switch is two fold in the closed position it tells the engine to idle but in normal operation helps to feed the sensors (don't know what). The engine should still run ok with disconnected if it's not working.

The other thing to think about is the fuel regulator, don't know how to test it but on mine it showed up as a problem on VAGcom.

Good luck, when you get it sorted please post on here as we do seem to have so many similar symptoms with the AAC petrol but a variety different of causes.

Cheers

Chris
 
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