Revs hanging/sticking when cars up to temp

[CMK5]

Hoping for some help with my gti it’s had an annoying problem since buying it and can’t seem to get to the bottom of it! It’s a 2007, stage 1 map, full exhaust and ram air induction kit! Every time the car gets up to temp the revs don’t like coming back down in neutral and when driving doesn’t matter what gear your in if you let off the accelerator the car literally drives it’s self seems to be a lot worse in lower gears it’s literally as if cruise control is on when it’s obviously not! It starts absolutely fine and drives lovely apart from the above I’ve got vcds and was getting code P0507 which wouldn’t clear but since changing the rocker cover gasket it’s cleared and hasn’t come back I’ve also done a throttle body realignment/adaption which was no help and it’s not showing no misfires at all any help will be massively appreciated It’s had all new genuine parts fitted listed below 
R8 coils
Ngk plugs
Rev g diverter valve
Pcv valve and hoses
Vacuum pump seals
Brake booster hoses
Dipstick
Rocker cover gasket
N80 valve

[mk1_dave]

I had a similar fault, everytime you went full throttle it would hang for a few seconds then slowly come down. Was also misfiring slightly on idle aswell turned out to be the MAF. Check your MAF has the seal and see what condition its in, I managed to swap my MAF with a mates to make sure that was the issue before I went out and bought a new one.

Think there is a way to test the MAF on VCDS but can't remember what you have to do.

[GVK]

http://www.ross-tech.net/vag-com/advertising/DiagnosingA_MAF_TechTip.pdf

MAF test - air mass in g/s group 2 on vcds, do a full throttle run in 2nd or 3rd gear, log it and view data

Assuming
this test is done at or near sea-level, the peak output of the sensor in
g/s should be roughly 80% of the rated horsepower of the engine , so you get your g/s peak reading and divide by 0.8 to give a theoretical peak bhp engine power. eg 200 g/s divide 0.8 = 250bhp.

Also check out fuel trims , a high adaption or trim could mean the ECU is trying to compensate for a lean issue/air leak or whatever.

Ross tech have videos explaining this in more detail.

[CMK5]

I had a rough idle and a misfire showing on cylinder 2 but those went away when changing coils and plugs, I did clean both maf and map sensors both seemed fine, can anyone tell me what fuel trims should be at idle? I was reading fuel trims the other day and group 032 would stay at 0.7% and group 033 would be constantly changing from -4.7 to 0.4 and a load of other numbers in between is that normal? I’ve got to nip out in a bit so I’ll take vcds with me and see what the maf reading is saying! When I was getting code P0507- idle control system higher than expected I thought that would be the issue as when trying to clear the code it wouldn’t but since changing the rocker cover gasket and clearing the code it hasn’t come back but cars still doing the same thing

[CMK5]

Just been out in the car had a look at maf readings and in 2nd revved right out it’s only showing 180gs