Fuel cut problem Experts please help


New member
May 5, 2023
East Halton
Leon fr 1p (cr)
Hi everyone,

First let me say yes i've searched the forums and googled my issue with no specific answer that helps me.
Also yes i know diesels power is all low and not high in the rev range however the fact is my car shouldn't do what it's doing and makes me nervous pulling out of layby's or overtaking.

Seat Leon FR Mk2 2.0 TDI Common rail (Not pd)

Posting here because many vw share my engine and this section seems way more active.

Had car 6 ish years, remapped and dpf gone a week after buying it. It's driven perfectly for years problem free (mostly motorway miles) HPFP failed at 145k, i've just replaced the entire fuel system front to back using genuine parts and bosch parts from an authorised bosch workshop in germany.

My car used to accelerate really hard through all gears to 5k rpm if i wanted but now after 1500 miles driving since rebuild i noticed when pulling out of a layby that it falls on its face at 4k rpm 2nd, 3rd (Worst) and sometimes 4th but i never really get going that fast. I have no eml or warning lights and i have genuine vcds and cable.

How can i diagnose if it's low fuel pressure (Fuel starve), insufficient inector etc? or anything else that might cause this? I'm concerned i may have been sold parts that 'fit' but aren't identical to what came out and they can't cope. I'd like to get a proper remap on a rolling road done rather than the generic map it had flashed years ago.

Other things to note

  • Idling high fuel pressure is good at 220bar - 260bar
  • I coded injectors properly no issues
  • I cleared codes from rebuild but havent scanned again to see if this fuel cut issue has caused any more stored codes. Ill edit post when i've scanned again.
  • I'd like to live log some paramaters using vcds and deliberately cause it but i'm not an expert with vcds and unsure which items to graph.
  • Car literally drives perfectly in every way except when i hit 3.5 - 4k RPM
Thanks a lot :)

EDIT: After deliberately causing the cut and rescanning there are no stored codes for the engine.