Engine surging

[Spark plug]

My engine has started surging when in drive or reverse but idles smooth in neutral and park. Anyone have any ideas y she is doing this?  Thanks (been a lot of heavy rain lately wandering if water has got into the electronics).

[ColinBarber]

At idle or when driving?

[NemesisUK]

47 minutes ago, ColinBarber said:

At idle or when driving?

 

1 hour ago, Spark plug said:

 but idles smooth in neutral and park. 

 

[ColinBarber]

Sorry, let me rephrase. Do you feel it also when driving?

[Spark plug]

Only when throttle is closed she should creep smoothly but surges. Drives smooth the rest of the time 

[ColinBarber]

I'd start with checking your Battery voltage when in gear. A poorly performing Battery or alternator could be the cause - when in gear at no throttle the rpm of the engine is lowest and therefore there might not be enough voltage for a good ignition.

Try idling in drive and then turn on your headlights/full beam to see if it gets worse.

[Spark plug]

Thanks I'll try that. Alternator was replaced a couple of weeks ago which flattened the Battery. And I charged the Battery for about 48hours which is  only new a year ago 

[is200 Newbie]

Could this be a possible issue with air intake? Blocked or dirty air filter or maf meter needs cleaning?

[Mr Vlad]

Why did you have the alternator changed? Were you having the same symptoms before the alternator was changed?

In August all he'll broke lose with my cars electrics. Dash lit up like a Christmas tree. Lost power steering but one thing I did Not lose was driveability. No surging of revs at any point whether I was idling or driving forward or backwards. 

Personally I think your problem is not Battery influenced. More like a fueling issue. Clean the throttle body and the MAF sensor (look on YouTube how to do it).

[ColinBarber]

2 hours ago, Spark plug said:

Thanks I'll try that. Alternator was replaced a couple of weeks ago which flattened the battery. And I charged the battery for about 48hours which is  only new a year ago 

A cheap alternator or a proper Denso one? This is the likely culprit given it is a recent change to the vehicle and now you are having problems. Also strongly matches someone else with who had the same issue:

 

[Spark plug]

The old alternator flattened the Battery not the new one and it wasn't  cheep. She was running well until the very heavy rain the other day. had to drive through lots of flooding so I still think it's wet has got in some were. Haven't used her since yesterday hoping she runs better when she drys off in garage

[Spark plug]

On 10/31/2022 at 5:49 PM, Malc1 said:

they all don't have the storage capacity ......  my local Asda stores don't have E5 , nor some of my Sainsbury's either and the likes of BP, well, last weekend I filled up with E5 and the difference in price was a staggering 14p a ltr rather than the usual 7p or 8p

The island of Ireland probably has some further limitations with storage and volumes of types of fuel being sold too

Good luck with it all ....  my E5 garages i now know locally here in my part of Kent

Malc

 

[Spark plug]

Just now, Spark plug said:

 

Thanks I'm making a list of stations 

[Spark plug]

Engine back to running much better today. I think it must have got water in something and it's dry now

[Spark plug]

On 11/27/2022 at 5:56 PM, Mr Vlad said:

Why did you have the alternator changed? Were you having the same symptoms before the alternator was changed?

In August all he'll broke lose with my cars electrics. Dash lit up like a Christmas tree. Lost power steering but one thing I did Not lose was driveability. No surging of revs at any point whether I was idling or driving forward or backwards. 

Personally I think your problem is not battery influenced. More like a fueling issue. Clean the throttle body and the MAF sensor (look on YouTube how to do it).

Mine did this too then cut out and wouldn't restart and I replaced the alternator and everything was fine