christmas day doing the rounds, and my car decided to cut out engine check light was not on nor the cat light.! switched ign off and on and noticed the engine check light and cat light both not on. all other dash lights ok .
car would crank but not fire . few min's later both lights came on when ign switched back on and car started and drove fine . since then the fault has been present when warming up and when driving just cuts out when ever it feels like hot or cold . any help would be ace as car is at moment main vehicle . car is a my94 import impreza saloon has full turbo back system, esl ecu, induction kit . tracker .cat 1 alarm .

 

start with basics check coil packs are tight and have good conections clean earthing straps on engine and battery, may be just a connection come loose somewere

 

removed and claeaned earth contacts removed and cleaned coils also removed ecu checked and cleaned contacts started car ran for about 10 mins then cut out again same as before also noticed waste gate actuator clicking when fault present .

 

Hopefully this may help you to diagnose the concern, I am assuming the engine light is still coming on.

Diagnostic Connectors
There are Two Sets of Diagnostic Connectors located under the Dash.
The Read Memory (Black) Connectors and the Test (Green) Connectors.
These connectors are always disconnected for Normal Driving.

To Extract Memory Codes:
Connect the Read Memory (Black) Connectors.
(Do NOT Connect the Test (Green) Connectors)
Switch Ignition ON
Read Fault Codes as Flashes of the Check Engine Light.

To Test with Engine Running:
Connect the Test (Green) Connectors.
(Do NOT Connect the Read Memory (Black) Connectors)
Start Engine
Read Fault Codes as Flashes of the Check Engine Light.

Fault Code Table

Code # Circuit and Status

11 Crankshaft Position Sensor
No Signal from Sensor with Ignition On,
Short or Open Circuit between Sensor and ECM.

12 Starter Switch
Incorrect Signal, Open or Short Circuit

13 Camshaft Position Sensor
No Signal from Sensor,
but has Signal from Crankshaft Position Sensor, Short or Open Circuit between Sensor and ECM.

21 Engine Coolant Temp Sensor
Incorrect Signal, Open or Short Circuit

22 Knock Sensor
Incorrect Signal, Open or Short Circuit

23 Mass Air Flow Sensor
Incorrect Signal, Open or Short Circuit

24 Idle Air Control
Valve Function Incorrect, Open or Short Circuit

31 Throttle Position Sensor
Incorrect Installation, Signal, Open or Short Circuit

32 Oxygen Sensor
Sensor Function Incorrect, Open or Short Circuit

33 Vehicle Speed Sensor #2
Incorrect Signal, Open or Short Circuit

35 Purge Control
Solenoid Function Incorrect, Open or Short Circuit

38 Torque Control (Auto)
TCM Signal Incorrect, Open or Short Circuit

42 Idle Switch
Switch Signal Incorrect, TPS out of Adjustment, Open or Short Circuit

44 Wastegate Control
Solenoid Faulty, Open or Short Circuit

45 Pressure Sensor or Exchange Solenoid
Sensor or Solenoid Faulty, No Manifold Pressure, Open or Short Circuit

51 Neutral Switch
Incorrect Signal, Open or Short Circuit

Fault Codes

The Check Engine Light (CEL) on the Dash will illuminate when the Ignition is switched On.
When the Engine is started, the Light will extinguish.
If a malfunction in a Sensor or Circuit has been detected, the CEL will be illuminated.
Fault Codes can be read via the Check Engine Light in the form of Long and Short Flashes.
Long Flashes represent the Tens and Short Flashes represent the Units.

Fault Code Erasure

Connect Both the Read Memory and Test Connectors.
Start Engine
The Check Engine Light will blink the OK Code (0.5 Second Intervals)
Disconnect Both the Read Memory and Test Connectors.

 

this dont work the engine light is inop when fault is present. and when the fault is not present checked fault memory and no fault has been recorded. starting to think its somthing to do with supply to ecu or even a ecu fault what do you think ??

 

I take it your foot is of the pedal when the vehicle stalls (de-accelerating), if so you may have a gummy IACV it wont show a code because it is still working within it's parameters electrically just not physically. It's somewhere to start.

 

but it happens at idle when i leave it to warm up as well as drivng . will check anyway just seems bit strange that the engine check light dont work when fault occours . can faulty componants disable ecu ?

 

think ive sorted it now ! i stripped down multi plugs going in to ecu and cleaned contacts some were very dirty!..
started fine and not had problem since .
thanks for all your help guys .