S5 2009 4.2 v8 - new owner question please

[AudidoThat]

Hi all.

I have just bought an s5 that was sold as lumpy on cold start, But once warm its fine.

It arrives tomorrow , but have seen many video's from the owner on start up and idle etc once warm.

I plan to do a carbon clean on it. and as far as i know its had the plugs done. But i cannot verify this.

I have seen a video where its rough on starting, very rough lol. spluttering and misfires 

But after 2 - 5 mins its ok. But still slightly spluttery as it hasnt been used in a while.

No smoke or anything from the exhaust / engine

If the carbon clean dosnt solve this issue. What would be any ones next point of action please.

The carbon guy will be reading the codes etc tomorrow , may have a better idea then.

But seeing as it gets better once warm, I wondered if anyone might know what that might points to or suggest.

Many thanks in advance.

Mark

Edited 16 hours ago by AudidoThat
missing information

[Steve Q]

Welcome to the forum you'll find the members on here are a friendly and helpful bunch 🙂 

Sounds an interesting project. You'll definitely have a better idea after you've got fault codes. How much service history is with the vehicle? 

Can the seller give you any idea of what work they've done to resolve the issue? 

Could it be a cam sensor, crank sensor, maf sensor or a fuel delivery issue?.

[AudidoThat]

Thanks steve,

The car is 2009 with 84,000 miles. Says it has lots of history with it, and apart from possibly doing the spark plugs, I dont think the seller has done much as it was a px for them. and they cant throw any more money at it, so i got it a bit cheaper. it hasnt been driven for nearly a year as its been sat in their yard as its the lower end of cars they usually deal with. But the issue was present before it sat for a year,

Maybe best is to report here the fault codes in a day or so once done,  and go from there. 

The carbon clean is being done on thurs, so i will know more after that

Thanks for the reply tho

Edited 14 hours ago by AudidoThat
spelling error

[Steve Q]

I hope the service history gives you an idea of what parts have recently been changed. My worry, is that the cars been px'd because of the issue either because the previous owner found it was going to be an expensive repair, or they had enough chasing the issue and spending money on various parts to fix it. 

[Magnet]

Welcome Mark,

I fear you are about to throw your money away by engaging in this ‘carbon clean’ - a bit like putting on your best designer gear, when you haven’t changed your underpants for a week! 
If it were mine:- 

Check how much fuel is in it - hopefully not much - and add 2 gallons of E5 to which you have added a fair dose of Redex. (See this morning’s response to a similar issue with an aging convertible).

Get it plugged in and find what codes are showing.

It seems you have been told it has service history, but you have not seen the evidence before committing to buy. Bit of a chance taken there, but….

I would certainly keep my ‘carbon clean’ funds as far down in my pocket to render it inaccessible. 
Please let us know how you get on Mark.

Regards,

Gareth.