Deceleration issue

My 2002 Vauxhall Astra 1.8 SRI petrol has engine issues when decelerating. Upon starting the vehicle, if the ABS and traction control lights are illuminated, the car will cut out when decelerating. If I exit my driveway, when I begin to dip the clutch and the revs fall, the engine will cut out. This will also happen if you are driving and, say, come to a roundabout – the deceleration will cut the engine. I am now able to bump-start it to keep going.

If the engine is started and these two lights do not show, then the car will not cut out. Likewise, if the lights show and the engine cuts out, simply removing the keys from the ignition and putting them back and restarting the engine will cause the lights to go out and the car will be fine until the next journey – at least 90% of the time. If the lights are not showing, the car will have no engine issues at all.

Sometimes when pulling away, if the revs are not kept at 2500-3000rpm there's no power whatsoever and it goes into ‘limp-home’ mode; this is solved by dipping the clutch and giving it some revs.

The Astra had an engine issue around a year ago, which was found to be a failed injector. The plugs, coil pack and injector were renewed and the ECU was remapped. Ian Porter

The traction control will cut engine power if it kicks in, which would explain the loss of drive. The problem will be within the ABS system – if you can get the codes read to check for any errors, this may help pinpoint the source of the fault.

As the problem is intermittent, it may not be a faulty sensor, but a faulty connection to the ABS unit or a problem within the loom. One common issue that could cause the symptoms you have is water ingress into the wiring harness, particularly in the multi-plug junction at the bulkhead.

This has been highlighted by Autodata and one of the first checks would be to undo the multiplugs and ensure the connections are clean and dry. If damp is found in the loom, then splitting the outer sheathing of the loom, drying it out and cleaning all the connections before reconnecting and resealing the unit may be a remedy. If no damp or poor connections are found in the ABS system, it may be worth checking the continuity of each ABS sensor and the condition of the reluctor rings. If the sensors or reluctor rings are okay, the fault is likely to be in the ABS ECU.