After service car running lumpy.

[Gav66]

As title says, car went in for a service at local vw/Audi guru...used him for years, anyways changed filters oil and spark plugs, checked for codes before and after, no codes, after he started it the engine was running lumpy i.e. revving high then dropping back down, no codes. He used a spray like wd40 to make the air filters go back on easily ??? He reckons that could be the problem. Also checked the battery which wasn't holding a charge like it should so ordered a new one. Drove home(15 mile) still not running the way it was, going back on Friday for the new battery to be fitted. Could it be the battery or should I point him in a different direction.
Any help will be very much appreciated.

Gav.

[Gav66]

Sorry wrong section.

[douglas96]

I know this was posted in error but it may be worthwhile getting VCDS or similar on to the car and checking to see if any misfires are happening live by going into "Measuring Blocks" and using the groups listed here -

(http://www.ross-tech.com/vag-com/m_blocks/010-019.html)

to check if a cylinder is misfiring. Not all misfires will throw up a fault code so one of the easiest ways to see if one is occurring is to use the Measuring Blocks function of VCDS or a similar tool.