why does my vw jetta 2.5 idle go up to 3000 then back to idle over and over

Question

2006 vw jetta 2.5 coded p0507 and p0171.idle surges to 3000 rpms then drops to 1000 over and over when stopped or with clutch pushed in.probable causes.cleaned maf and throttle body as well as replaced the air cleaner.please help

Answer 1

P0507 Idle higher than expected

P0171 Fuel trim lean bank 1

You have false air or vacuum leaks,Any vacuum leaks that gets past the MAF is false air that affects the idle condition, This is what causes the surge in idle.These can come from ruptured vacuum hoses, or at the intake manifold. or a open EGR valve.