Ford focus 02 auto intermittently stalling

[Jay_61279uk]

Hey hopefully someone can shed some light on this, my partner has an 02 plate focus 1.6 auto that keeps stalling, it doesnt happen all the time, more so in wet weather though. Its usually when slowing down thn accelerating off at junction etc, the battery light will come on then split second later car will chug lose power and stall. I have recently changed timing and aux belt, fuel and oil filters spark plugs, exhaust and lambda sensor, also when driving in bad wet weather the engine light will come on with something o2 sensor related but clears when wipe code, not sure if this is jus water getting into the sensor! Any help greatly appreciated

[v530anh]

Which lamba sensor did you use?

[Jay_61279uk]

Erm..pass! Was replaced cpl month back, was the pre cat 1

[v530anh]

You can try to disconnect it see if it runs better. Just disconnect from connector.

[Jay_61279uk]

Would a bad sensor cause it to stall though?

[v530anh]

Symptoms of a Bad Oxygen Sensor. When you have a bad oxygen sensor, your vehicle will run less efficiently, it can sometimes have a poor idle,erratic jerking at steady throttle, hard starting problems, cause the check engine light to come on, and will cause high fuel consumption.

[Jay_61279uk]

Theres no erratic idling, only just before it cuts out, when restarting car it fires up first turn of key. Doesnt cut out all time, just every so often, becoming more frequent lately though

[ace666]

Have you checked the that the battery is still good.

[Jay_61279uk]

No, seems to be ok normally, holds charge etc but could be a bad connection somewhere i spose

[F0CUE]

Sounds ignition related get your coil checked.

[Jay_61279uk]

Had the car for a diagnostic check today and came up with no fault codes

[v530anh]

For such an old car it may be worth checking if the throttle body is dirty. You can use an air intake cleaner spray to clean it, not wd40 as it leaves a residue.

[FatHead1979]

2 hours ago, v530anh said:

For such an old car it may be worth checking if the throttle body is dirty. You can use an air intake cleaner spray to clean it, not wd40 as it leaves a residue.

I recent cleaned the throttle body on the MK2.5 1.8 petrol that I bought the wife as the car was hanging onto revs.  The throttle body was BLACK inside but a can of carb cleaner and few washing up scrubbers saw to that.

I'm not sure how easy it is to remove on the old 1.6 engine but I'm sure some of the more knowledgeable people will be along shortly to walk you through it!

[Tdci-Peter]

On 15/08/2017 at 0:19 PM, Jay_61279uk said:

the battery light will come on then split second later car will chug lose power and stall.

If it was a mechanical problem like throttle body, then I would expect the battery light to come on after the engine has started to stall, and rpm has dropped to a point where the alternator can no longer supply the battery voltage.

This timing could be very hard to truly judge in a moving car. But if not mechanical, then it may be electrical. Bad alternator is unlikely: light would come on, but the car would run ok on the battery. Bad battery, or battery connections is possible: ripple and varying voltage from the alternator could upset the ECU. Bad earths, especially the ones from battery to engine, and to body, are also possible.

If it is engine related (stall starts before battery lamp on), then coil pack & throttle body seem the most likely remaining culprits.