engine 'cough'

[tony-tvr]

I've had my 4.5 for a couple of months, but the engine has a slight cough when holding steady speeds between 10 and 70mph, the dealer assures me this is normal on cerberas (un burnt fuel igniting somewhere). Anyone out there had the same problem and found a cure?

[_DJ_]

tony-tvr said:

I've had my 4.5 for a couple of months, but the engine has a slight cough when holding steady speeds between 10 and 70mph, the dealer assures me this is normal on cerberas (un burnt fuel igniting somewhere). Anyone out there had the same problem and found a cure?

Could you describe the 'cough'? Unburnt fuel generally just results in banging as the fuel ignites in the exhaust. If it's kangaroo-ing, then it's probably just your throttle pots which need sorting. Either replace them (30 quid each) or speak to Joolz about his mods to prevent it.

[kojak69]

I would also say the throttlepots. If not, try the HT leads.

[tony-tvr]

No, not the exhaust noise, hell that noise I'd keep even if it was a problem, and no, there's no kangerooing either, performance is still shattering and uninterrupted. The noise is just a like a 'cough' not a bang or popping like the exhaust. It come is two or three short bursts, then stops and happens again a little later.

[suffolkfox]

Based on similar previous posts, if it's when your holding speed or on overrun, could be the linkage between the two banks. If it becomes loose due to wear, at steady speed the two banks can be fighting against each other, and this can cause occasional rough running.

[joospeed]

sounds like you probably have one or two cylinders drawing more air than the rest, these will be running weaker and you're probably hearing the spit-back through the inlets that results.

[tony-tvr]

Thanks for the hints, gives me something to work with.