My Passat commuting workhorse has developed a bit of a strange fault, it's been going on for a while now but seems to have got worse over the last few weeks.

It's a MY00 1.8 20V petrol (not a turbo).

It manifests itself in two ways:

1) Cold start: idle fluctuates sometimes, i.e. revving up then dropping almost to stall. It's then pretty ropey for the first few minutes of driving and the last few days sometimes it won't rev at all when a bit of throttle is applied, just splutters and won't go over 1500rpm.

2) Underload / high speed: Say you're doing 65mph in 5th on the motorway, stick you foot down and it just won't pick up. You can feel it hesitating and being a bit lumpy, then all of a sudden it will start to pick up a behave as normal all the way up to the speed limit

It's a bit like a Scooby MAF failure but could be something else I guess Last time I had it serviced coil packs were mentioned. No check engine light, don't know if the ECU would be storing any fault codes.

Just thought I'd see if anyone has any ideas, I've got it booked in for next week anyway to get it looked at.

Thanks!

 

Hi Mate,

if your local in the cheshire area I have a Vag Com so can do a scan on it if you want?

Cheers

Stu

 

Chances are its a VW MAF failure. Very common and easy to fix.

 

very common on vw. also one thing to check is the coolant temp sensor. this was a common fault as well

 

Thanks very much for the offer but unfortunately no where near Cheshire

 

Okay, money is on the dreaded MAF then

I tried to do the test that I used to use on the Scooby, i.e. when the engine is warm and running unplug it, if it stalls MAF ok, little or no change to revs MAF bad, but couldn't figure out how to get the connector to come away. Admittedly I only spent a few minutes trying and didn't try with a screwdriver or anything.

 

ECT is very very common too

 

+1 for the Get a bosch one from euro car parts. CTS isn't the most likely, although they do go but they generally show themselves as an erratic temp gauge on the dash

 

It turned out to be the Lambda sensor, though he did say that the MAF was operating just inside of the tolerances on their diagnostic system so could be next.

Anyway now running nice and smooth again and hopefully will stay that way for a while