my engine management light keeps coming on and diagnostics tell me Fuel Trim: Bank1 System to lean and code P1136? This only started when i had the coil packs replaced. Get it reset and it comes back on again. Any ideas please

Edited 11 April, 201313 yr by technician25

As quoted from Ross Tech Wiki

17544/P1136/004406 - Fuel Trim: Bank 1 (Add): System too Lean

Possible Solutions

• Check Mass Air Flow (MAF) Sensor
  
• Check Fuel Pressure Regulator
  
• Check Fuel Pump
  
• Check Intake/Exhaust System for Leaks
  
• Check Secondary Air Injection for Leaks
  
• Check Vacuum Lines for Leaks
  

Special Notes

• Fuel Trim Info
  
• When this fault is stored and external vacuum leaks are not found, less obvious problems may be present:
  
  • Check Evaporative Emission (EVAP) Canister Purge Regulator Valve (N80)
    
  • Check Brake Booster and Hoses
    
  • Check Electric Vacuum Pump ( If Applicable )
    
  • Check Crankcase Ventilation System for faulty components. When the PCV or Crankcase Ventilation System is faulty, vacuum is typically present under the oil cap and misfire faults are common.
    

So start by unplugging the MAF and see if it runs worse. if it runs the same that could be the sign of a knackered MAF

Edited 13 April, 201313 yr by Gtiracer

Split pipe somewhere, either the 'Y' pipe or one of the pipes buried under the inlet manifold.

Indeed vac pipes commonly break down on these models, had to replace one already myself

Ignore

Edited 13 April, 201313 yr by Gtiracer

I had the same code, vac pipes as said above. On mine, it was the small one connected to the underneath of the inlet manifold . Bit fiddly.