gti t 20v lacking performance

[l4v15]

hi. im new here. just bought a mk4 1.8 t gti 20v. tis an s reg 150bhp(apparently) with 75,000 miles. feels like it is lacking performance. very strange, almost like a normally aspirated 1.8 really. maybe a slight missfire at certain rpm or flat spots or something, but acceleration isnt what it says it should be on parkers guide specs. are these cars generally quite slow as standard or what. my old astra g coupe bertone 1.8 was defo quicker than this. but shouldnt be according to specs. thought turbo wasnt working at first but i can hear it spinning. changed spark plugs and coils are fine on tick over. any ideas or r they just not that quick. chearz steve

[Conker]

Check its average MPG over a decent run, that would give us a clue  -  It could be clogged injectors etc. When I first got mine it took me a while to realise that its faster than it feels, mainly due to the quietness of the cabin compared to rivals (thicker glass etc.). Also I think the 1.8T's has specific strengths, e.g. it isn't that quick off the lights, but it is very torquey up hills, at motorway speeds in 4th gear (try 70 to 90mph!.... On a private road of course), and at overtaking.

It is a heavy car though. But on the other side of the coin you get quality materials and manufacture.

If you describe the symptoms a bit more someone might be able to suggest a few possibilities. The MAF is a common problem, and might cause the problems you describe.

[l4v15]

sort of 30-32mpg on an average, not to bad really. whats maf? yea i guess it could be normal then taking into account the things uv said. better get modding i guess. chears mate, steve

[Conker]

I get 36 mpg average (thats the long term average). If I was you, the first two things I'd do is chuck a bottle of redex advanced through it (made a big difference to mine), and then after you've used up that tank of fuel try and test the 0-60 time (somewhere safe). You can't test it that scientifically, but so long as you get around 8 seconds, its fine.

MAF is the airflow sensor and its critical to optimal engine performance. Mine has never gone wrong, but apparently its quite common, especially if you fit an aftermarket air filter. Have a search in the Mk4 section - theres loads of posts on it.

[l4v15]

ok great, il do that. i unplugged the maf on the side of the airbox earlier to see if i heard the engine note change, and it stalled, so id say that isnt the problem, lol. could be fine. il try the redex, maybe just a bit of carbon build up or sumit. chears man