I agree with BT it seems far too cheap.

Unless you have it properly examined you cannot be sure it is not the gearbox and they are certainly not cheap.

It's cheap because the fault is undoubtedly expensive. They'll have had it in and diagnosed. It's a car for an auto technician or sparky as they will be able to put the labour hours into it without having to price it for a sale.

If it will not go above 30 it could be some dead Injectors, this would also keep it from changing gear as it would be like driving up a hill all the time.

As to Computers the Computer is only as good as the guy who knows how to operate it, we know that on hear as there is a lot of guessing in trying to help others with there pc problems. It’s a lot woes in a garage where they have the equipment but do not know how to operate it

It's been my experience that it's not the cost of the car thats the problem, its the cost of running it that is the deal breaker for me. (I've also noted that when someone says a car is 'too big' for them then usually it's a financial term whether they realise it or not). This also includes repairs for known troubles as well as the obvious biggies insurance group and mpg.

Just remember that as in all things if something looks too good to be true trhen it usually is. If you do buy this merc, then hope for the best but expect the worst.

WTM

btw, for what it's worth I'd walk away from this one.

I agree. If it is the ECU then you will be looking at a bill in excess of £400 to replace it.

Do not touch it with the proverbial barge pole.