Audi a4 1.8T

[cardoctormatt]

Hi folks iv an Audi A4 1.8T w reg its a great car and im loving driving it but have a small problem. When i lift off the power it hesitates for a split second before i put the power back on has anyone had the same problem?

[AAT1981]

Coil pack...

[00161wj]

I love how the answer to all audi problems is a coil fault. More likely to be an n75 valve or the air mass meter. Try cleaning the air mass meter

[istoo]

eliminate the obvious ones, try the fault codes being read first...

any of the above are possibles, the N75 (boost controller) being sticky will feel like boost going on and off, in pretty much all gears. these are prone to failing if you have had the car remapped. common replacement being the N75J (i believe the TT one). Had this fail in mine.

The MAF when they start to go usually coming up for 100k but can be earlier or later, is the economy and performance just start to drop off all together. Take care cleaning it use a lint free rag and some carb cleaner.

coil packs can be a problem, but as pointed out there are other possibilities.

other one i have had similar on the 1.8T is the cam speed sensor, it was giving faulty readings and hesitant acceleration. Last but not least, check it for boost leaks, not always obvious i found 3 cracked/split hoses just cleaning the engine bay when i bought ours!

[nicktowe]

00161wj said:

I love how the answer to all audi problems is a coil fault. More likely to be an n75 valve or the air mass meter. Try cleaning the air mass meter

failing that...coil packs

[cardoctormatt]

Thanks guys for your help ill have a better look when i get home. Dont think its the coil packs as it runs realy smooth just feels like it is lacking the boost pressure to me compared to when i first got it.

[cardoctormatt]

Wheres the N75 valve and wot does it do

[Mastertech]

Check the thin black vacuum pipe in the front of the inlet manifold which runs along the front of the timing cover. There's a good chance it's deteriorated and split with age. Causes an air leak and running problems.

Unlikely to be a coil.

Edited by Mastertech on Saturday 20th December 21:01

[cardoctormatt]

Thanks mate sounds like it as i removed the air box to tighten my turbo back on the exhuast and it was after that it started to be hesitant then gradualy startd loosing a bit of boost so i think i might have distured it

[nail_it]

If you are replacing the pipe might be worth upgrading for a better material ie Forge do some more substantial kit

[cardoctormatt]

Thanks to every one im sure ill fix it when i finally get home. Will let you know when iv sorted it or you will see a black A4 whizzing down the motorway lol