Shudder on accelerator and rising fuel consumption

[Krypton87]

My Passat 132TSI is over 8 years old and has done 70K.I am getting a slight shudder on the accelerator while moving off from rest. The fuel consumption gauge hits its max value of 20L/100 km while moving off and slowly it drops to sensible range after doing about 10KM plus but still seems to hover around the 10L/100 km mark on a 60-80 km road in a smooth flowing traffic. Any thoughts on what could be the issue?

[Lucas_R]

Are you getting any lights on the dash flashing when the shuddering is happening? It could well be misfiring due to failing ignition coil packs and/or spark plugs, seeing they are 8 years old.

You really need to hook the car up to a diagnostic device to interrogate the cars computer to see what its not happy about. If you do not have one, you can either buy one (a handy and good investment between $150-300 for a good one like OBDeleven or Carista) or take the car into your mechanic and pay to have them hook up to their diagnostic machine. As a last resort, I know Supercheap Auto can run a generic scan on your car for a small fee.

But a misfire seems like the most likely culprit and this will cause the shuddering and also have a negative effect on fuel consumption. But misfires are usually accompanied by a flashing light on your dash if the problem is bad enough.

[Sharkie]

Second sparkplugs or coil pack failures. A scan will tell you which cylinder is misfiring.

[Krypton87]

Many thanks Lucas and Sharkie for your advice. I am a novice with these things. Will something like this do the scan for me?

https://www.amazon.com.au/ANCEL-AD410-Enhanced-Automotive-Emission/dp/B071FSNL73/ref=sr_1_1_sspa?crid=3TPJA28RGK3Q8&dib=eyJ2IjoiMSJ9.Hg7oivpm2f-uTacxaqpmHa0FkCS4h5GgGEJL4j9f373R8vAbt4mF7bbSg5icks3oiZ8MY5Nsww0MC-qV7eQqNoIAO_byDzR2TV58EIIkf2xF0SxkgZd29s5TJlx9jknaAUrrZ5tpWvziKYQdFK4LiSmz3utIqSUMV8KaMKjetyM7hmor5_-ZPmIBAK3zRSJWk5DRB0ZWfxMlJ6hJvSFJukgw6INsra7AkZ0ydXGfFi3UT3gGOcQEtTio6c5ee2ZDZXxEC-2z0PZJYII7TnjzNxydNR3VDfpcLX6xhJ_eJE4.IYKW6eFZhHdkYMc9fkLWt7Gj4rEUoGTjSqIVJ6puFGc&dib_tag=se&keywords=obd2%2Bscanner&qid=1748591510&s=automotive&sprefix=obd2%2Cautomotive%2C275&sr=1-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&th=1

[Lucas_R]

If you want something cheap then id probably go with this one which has software on it for VW group vehicles. https://www.amazon.com.au/Diagnostic...07BS7PDC2?th=1

The one you linked to is a generic one that works on all brands but only does limited functions.

[Krypton87]

If you want something cheap then id probably go with this one which has software on it for VW group vehicles. https://www.amazon.com.au/Diagnostic...07BS7PDC2?th=1

The one you linked to is a generic one that works on all brands but only does limited functions.

Thanks Lucas, much appreciate your guidance!

[Krypton87]

Hooked up the ANCEL OBD2 tool with car running and went through all sections like engine, transmission ,electrics there were no codes. It may be worth noting that the high fuel consumption of over 10l per 100 km is very noticeable in the first run in the morning. My subsequent runs along the same route in similar traffic conditions give a lower consumption in the 8-9 range. Also noticed that when started from cold the engine idle speed is around 1100 rpm for couple of minutes and it drops down 900 after thereafter.