I have just brought this car and it has developed this problem within a week.

When the car is up to temperature it runs fine but doesn't feel as fast as it should be.from cold start in the mornings it shakes and shudders like mad and sounds as though it is miss firing. Please help

Hello Wes,

Thanks for joining.

I’m sure you will appreciate that it will be extremely difficult to diagnose the cause from a multitude of possibilities - without examining the car. 
Since you have only just bought it, it is possible that you could have redress against the seller. This would be my first consideration. 
Kind regards,

Gareth. 

 

Unfortunately the seller has ignored all my messages and calls 

Dealer or private sale? 

It was a private sale 

Unlikely to get a comeback on a private sale. You'd best getting a diagnostic check to see if any fault codes flag up. 

What's the service history of the car? What work has it had recently? 

Any fault codes? 

It could be a MAF sensor, coilpack, turbo etc. 

Hello Wes,

Even though it was a private sale, it must meet the description of the advert - that is why some people put a description of ‘Starts, Drives, Stops’, or words to that effect, to minimise any comebacks. 
Kind regards,

Gareth. 

It doesn't have much service history at all. The eml light comes on as it should when ignition is turned on goes off as normal, but doesn't come on when the car is having problems so isn't showing any codes. I did unplug the MAF but made no difference. There is no smoke or anything. Thank you 

My advice would be to get a garage to do a proper diagnosis. 

Wes.

From the limited description of the symptoms it's unlikely anybody can give a precise diagnosis because there are so many possible causes of the problem. Your best option is to have it tested professionally.

You have not mentioned the mileage but a 15 year old car is no spring chicken, and should have a long service history. The lack of any such history looks very suspicious.