tvr s2 2922cc lumpy running

[oldtrev]

help needed ive just bought a beatiful 1989 tvr s2 with a lumpy running engine (only between 1000rpm & 2000rpm)starts fine, ticks over fine, like a bullet from a gun through the gear box
but will not cruise smoothly( like driving a pogo stick) whats the cure???? leads, plugs,dizzy cap,
ignition coil all new is it a diy fix or take it to the tuners

cheers oldtrev

[lwt]

I had one a while ago. Best bet is to find someone who knows about Bosch ecu's (e.g. a bmw man). I had problems caused by previous owner 'mending' a broken throttle cable but making it shorter, then bending the throttle pot bracket to suit!. Other areas to look at are the air flow meter and air leaks in general.

LWT

[jimed]

I'd try a post on the S forum - the guys there are really knowledgeable and helpful and are more likely to see the request on that forum than the general TVR one. Someone may know the car/who owned it previously and hence be able to give you some pointers.
The 2.9 V6 in the S2 is a nice engine and not too hard to sort unless you are really unlucky so hopefully it will be something simple. As mentioned an air leak might give these sort of problems so that's worth checking as is the timing; maybe the idle control valve (front offside of the plenum chamber held on with 2 bolts so easy to remove/refit) might be worth cleaning but that may not give the symptoms you describe. Nonetheless it does get quite mucky inside so benefits from being removed and cleaned inside and this might help a little - spray with carb cleaner or similar and refit with a new gasket (you can make one yourself with some cereal packet card and use a little vaseline as gasket stuff - that works fine!).If you haven't already got it the Steve Heath book on the S series is very useful - the 2nd edition is the later version.
Good luck sorting it - the S is a super car with plenty of go and easy to handle and maintain.
Jim