Flat spot ... help pls

[s2bug]

Hi all

Have a flat spot at 1800 to 2k revs and then 3500 to 3800 rpm, feels like no power and if you sit in that rev zone the van lurches about

......on my T4 syncro 2.5 petrol.

Sorry to be asking on this forum but its really bugging me and cant locate the problem.


Help would be great as not sure where to start.

[S2central.net]

MAF OK ?
Intake leaks ?
Lambda OK ?
Sparks / Coils ?
Changed fuel recently ?

[s2bug]

MAF OK ?
Intake leaks ?
Lambda OK ?
Sparks / Coils ?
Changed fuel recently ?

What is the best way to test MAF?
Intake all OK
Lamda OK,
Sparks all firing OK
Tried higher octane and the same issue



Thanks Paul

[S2central.net]

How do you know lambda is OK ?

Not being funny here - checked its output with a DVM or logged it in VAGCOM ?

As to MAF - tricky to test on the car unless you know the expected voltage output at say idle, 3000rpm (no load) and redline at WOT. You'd need another car or test MAF to compare with really.

[s2bug]

Tested emmisions when on MOT and were out as lamda connection shot, sorted connection and emmision OK!

Me thinks I am VW garage bound!


Thanks Paul

[mcandmar]

"T4 syncro 2.5 petrol" What engine is that?

Sounds like an O2 sensor acting up to me, do you get the part throttle kangaroo action?

[s2bug]

5 cylinder 2.5L!

Yes do get the kangaroo action if you sit in the range of 1800 to 2k and 3500 to 3800 rpm,

Any ideas where an `o` 2 sensor might be?