Rover 75 mis-firing
 

Hi Everyone, still got mis - firing on my 2003 Rover 75 1.8 Turbo. Some days are better than others. Worst especially around 2000 to 3000 rpm. Once when I refilled with fuel it corrected itself. It has corrected itself several times but the problem comes back. Any ideas. Regards Ken

A few things can cause a mis-fire, inlet manifold gasket leak, plug gap too big, hole in a hose, coil pack.:shrug:

From my own experience with a 1.8t- i always consider the coil packs and leads with a random multiple misfire as the first port of call. :shrug:

Check the vacuum hoses from the turbo.

Hi, thanks everyone for replies. From memory I think it was ok for several refills then problem came back. Car not used a lot now and only short journeys.Refills were about half a tank each time.Regards Ken

Another possibility Kenneth is the onset of fuel filter separation which reduces fuel delivery pressure.

Simon

Hi, can the fuel filter be changed without special tools? Thanks Ken

The symptoms you describe sound like potential turbo over boost, which will cause the engine to hesitate and miss fire before continuing . This will happen more under load and wide open throttle and may be the reason why the issue seems intermittent. As planenut said check your turbo control hoses for any splits or loose fittings , Also check the waste gate for operation as the have been known to seize .

Plug leads are known to deteriorate where they attach to the plugs and also the carbon ribbon in the leads can break down. Any moisture on the leads then leads to spark tracking to earth by the shortest route (ie to the head). This can often be seen as sparks jumping in the dark.