5000rpm

hello can any one help i have a mk2 ibiza cupra, if you build up speed slowly its ok up to 5000rpm then limits,but if you try to floor it it just dont go any were fast until you take your foot off abit,its standard apart from aftermarket air filter.i have checked timing

Had my 2005 LCR (fitted with K&N panel filter, Samco Induction hose and 4 bar FPR) on rolling road and got 217.7bhp. Remapped then back on rolling road and got 245bhp. Problem is when compairing old graph with new graph. Old graph showed bhp increasing way past 5000rpm and new one shows...