Idles rough possible vacuum leak

Welcome to 2CarPros.

A vacuum leak can come from just about anywhere. Here is a link that explains how to locate a leak. Take a look through it and let me know if it helps. Also, let me know what code you are getting.

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

I hope that helps. Let me know.

Joe

Welcome back:

The code indicates a lean condition. See picture 1. Since it is exceeding Lambda, either you have really low fuel pressure or a major vacuum leak. Have you checked fuel pressure? And you are certain there are no vacuum leaks?

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Here are the directions for testing fuel pressure specific to your vehicle:

13 31 029 CHECKING FUEL PUMP DELIVERY PRESSURE
Checking Fuel Pump Delivery Pressure (M54)

Special tools required:
- 13 3 010
- 13 5 220
- 61 3 050

Switch off ignition.

CAUTION:
The fuel in the fuel lines is under pressure (approx. 3 bar).
Catch and dispose of escaping fuel.

Remove cover from fuel injectors.

pic 1

Remove dust cap (1) from measuring valve on fuel rail.

pic 2

Prepare special took kit 13 5 220 (consisting of 13 5 221 and 13 5 222).

pic 3

Unscrew check valve (1) on special tool kit 13 5 220.
Fit special tool kit 13 5 220 on measuring valve and tighten knurled nut until hand-tight.
Start engine.
Screw in check valve (1) until a pressure reading is indicated on DIS Tester.

CAUTION: Do not under any circumstances screw in the check valve up to the mechanical stop. This could damage the valve in the pressure regulator housing.

Measuring fuel pressure:
- Connect pressure sensor to DIS Tester
- Start engine.
- Select Measurement.
- Multimeter function appears
- Select Pressure test
- Read off fuel pressure

Compare actual value of test pressure with specified value.
Switch off engine.

Checking fuel pump:
Detach fuel pump relay.

NOTE: Check whether fuel pump no longer starts up during engine starting procedure (engine fails to start).

pic 4

Connect special tool 61 3 050 to terminal (87) and terminal (30).
Press button and read off fuel pump delivery pressure on DIS Tester.
Compare actual value with specified value of delivery pressure.

pic 5

Keep special tool 13 3 010 ready for further tests.
Further tests are described in the section "Fuel pressure check".

NOTE:
Interrogate fault memory of DME control unit.
Check stored fault messages.
Rectify faults.
Then clear fault memory.

_____________________________

Let me know if I can help.

Joe