Does anyone have a valid answer?

perrya

Veteran Member
Joined
Dec 16, 2011
Location
california
TDI
2006 Jetta BRM with 200K
Many 2002 VW Jetta 1,8T, automatic, owners have had similar issues about to be described: When engine is cold, say overnight, and started then driven without warm up of 10 min, upon acceleration the car jerks or bucks some and\or seems to go into neutral (meaning, the engine does not stall, but there is no power to keep moving) for 1-2 seconds before accelerating again. This is a dangerous thing in traffic.

The mystery to this remains: if you let the car warmup for 10 min or more even after sitting for a long time, the car runs smooth and normal. Some have suggested it is grounds, but then, it should do this all the time not just when cold. Some think the turbo has to warm up first, but is it active in just idle? Some think its a tranny thing, but why just when its cold? Is this a calibration issue to sync the turbo to the tranny in the ECM? Is it a sign the turbo is failing?

Like others, there are no codes. Car has 100K on it.
 

benshaw

Veteran Member
Joined
Jul 8, 2004
Location
51
TDI
a4 130pd bew
im no expert.
I don't know how long u had it but have u changed the coolant temperature sensor? if its original I would for a genuine part only.
 

BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
Gas Engine.
Valid Answer, maybe.
These cars have several temperature sensors, check them all cold, then hot, look for wack readings. Other than that you got fuel mixture, timing, etc.
 

perrya

Veteran Member
Joined
Dec 16, 2011
Location
california
TDI
2006 Jetta BRM with 200K
The coolant temp sensor was changed, as to coils, if the coil was bad or intermittant, it would throw a code. As I said, there are none. It would also misfire all the time, not just when cold. It seems to be temp related-maybe there is no answer!
 

BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
Oh there is answer, and it will seem obvious when you find it.
Could the timing be way advanced? Air/fuel mix not adjusting to cold?
Embarrassed to say I don't really know exactly what the mechanism is for "choke" on these. Mix needs to a tad rich when cold.
 
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