Any trouble codes or dash lights indicating?
Any repairs carried prior to this?
Could be a throttle faults, restricted exhaust system or air intake.
September, 4, 2012 AT 7:21 PM
No trouble codes or any dash lights no repairs as yet
September, 4, 2012 AT 7:47 PM
Start by checking the basics, fuel filter, air filter and exhaust blockage.
September, 11, 2012 AT 4:39 PM
Might well be worth checking the exhaust manifold switchover valve vacuum pipe. The switchover solenoid valve sits in front of the egr valve to the far right of the engine bay. It has a (usually) white plastic pipe which runs to switchover valve at the right of the inlet manifold. If split or holed it will prevent the manifold switching to the longer manifold length and restrict your rpm and power as per your problem.
Hope this helps,