Passat suddenly losing power

Airliner

Veteran Member
Joined
Jan 15, 2005
TDI
Audi A4 1.9TDi Avant Quattro 2001 silver
Hi.

A friend of mine have a VW passat 2001, TDI PD, not sure how big the engine is, but there is two red letters in the "TDI" on the back of the car.

My friend reports to me that the car is suddenly loosing power (at first I thougt it was going into limp mode, but I'm not sure about that anymore), and the power may return after some driving, after the next restart, or the next day. It does not sound like there is some connection between the return of the power, and a restart.

I have checked with my VAG-COM, and there is absolutely no fault code logged in the engine module (even if that's a bit strange I think).

I have testdrived the car for some hours, but the fault is not showing up at this time.

So my wild guess would be: the catalytic converter.

But is there anything else I should think of ? And is there any tests that I could run with VAG-COM to confirm (or not confirm) the catalytic converter ? Would the intake manifold pressure increase A LOT when the fault exists and we drive with the computer hooked up to the car ?
 

2004STARWARSTDI

Top Post Dawg
Joined
Oct 19, 2004
Location
LAKELAND, FL
TDI
2004 Platinum Gray GLS Jetta / 2006 Silver Jetta with DSG
Loss of power

Some reasons: Bad or failing Maf
EGR and Intake manifold clogged
Need new fuel filter
Need new air filter
How many miles on car?
 

Airliner

Veteran Member
Joined
Jan 15, 2005
TDI
Audi A4 1.9TDi Avant Quattro 2001 silver
Tja, I have not been doing a "drive test" of the MAF yet, because I have some trouble finding the setup for my COM port card to my laptop. But the MAF is showing "good" flow when idling.

So what you mean is I should be doing a full throttle run in 5th gear (there is a 6 speed transmission on this car) and log the requested and "the current intake air mass" ?

I really don't think it's a clogged intake. The car has 150k km on it. But my Audi A4 have 160k km, and there is not very much "clogging" on that car. And I don't think the problem is so big in europe as it is in USA.
 
Top