splutter & judder

Hey, I had just replaced my brake master cylinder, and took the mk1 out for a test drive to check the brakes…….

It is a mk1 20vtagu with qpeng management.

Car was running like a dream, so stopped at the shops for some refreshments. When i drove off the car was spluttering and juddering!! There would be no revs, then the turbo would kick in, and i would get some power but have to change gear immediatley.  
Thought it was misfiring and i had blown the coilpacks (not the first time and the symptoms were similar). However when i checked under the bonnet it turned out that the air filter had fallen off!!!

fixed the air filter back on the best i could, but the jubilee clip was knackered. Took the car home and it was a lot better but not perfect(need to get another jubilee clip).

Would the symptoms of spluttering and juddering just be down to the fact that the engine was sucking to much air as a result of having no air filter? Or will i have to go out into the rain and check the coilpacks? Or is it something worse? :dontknow:

anything else that could cause such an issue?

I am not much of a mechanic so be gentle…

Thanks

Does it have a MAF?

not 100% sure if it has maf.

I think qpeng dont use it, I am no expert though.

It is just wierd that when i put the filter back on it ran a lot better.. so it was maybe a vacuum type problem, however i am just guessing as i know very little about cars…