hi there, i currently own a 940 2.0 turbo intercooler estate & i have a problem with a misfire & tick over. on initial start up from cold there is no problem at all, ticks over at 750rpm approx, as the engine warms up the rpm rises also, between 750&1500. when driving the car there is a misfire/hesitation through the
rev range, if you dip the clutch the revs will hold at around 1000/1200rpm.because of the misfire i changed , spark plugs, plug leads distributor cap&rota arm but still no different, then engine check light came on & fault code 113 came up on read out. on investigation found that the oxygen sensor had decided to call it a day, replaced with a new one erased check light but still has not cured problem, i have also renewed the fuel filter under the chassis,checked all wiring connections where possible & also checked for air leaks,air filter is clean as are all associated pipework, this car has run almost faultless until 2 weeks ago ,just gone through its mot without even an advise remark & 182000 on the clock please can anybody help. thanks

I would also check the injector firing and power module.

High idle and misfire suggest a vacuum leak in the intake system: the main air tube, a vacuum line, or the intake manifold gasket might be leaking. At 182k you might be in the market for some new intake parts.