K seies stutter / misfire under acceleration

[andydavy]

My xpower 140 seems to have developed an issue.

On hard acceleration it seems to stutter / misfire between 2000 and 4000 rpm. It idles and starts fine and has just passed MOT emissions tests. It has been sitting for a couple of weeks.

Lat trip it seemed to clear itself after a good hard run. This time it hasn't.

Any ideas where to look would be welcome.

[SM25T]

Any chance of water getting into plugwells ? If not, try unplugging lambda sensor cable, and if it runs fine without, replace the sensor ... dirt cheap these days on line. Don't buy from CC !

[Geoff Brown]

Is the engine pre-euro 2 with a dizzy? The cap contacts can be a problem but not usually the rotor arm unless it has never been changed or cleaned up.

Have the plug HT leads been checked of late? On my K series one of them had conveniently corroded to the plug causing a misfire. So much so that when trying to remove it the contact was left on the plug!

Otherwise normal checks - plugs & lambda. Or the horror of dirty fuel........

[Stridey]

Always worth checking leads with a multimeter , a ruler and a simple formula to work out resistance over length (Search you tube).... 

When I did this it revealed a lead that was out of kilter with the others.

[andydavy]

It's 2003 so assume its an EU3?? Also what spark plugs should it have?

[Jonathan Kay]

NGK BCPR7ES

Jonathan

[Wrightpayne]

A throttle position sensor reset TPS can sometimes clear faults - ign on but not running, press throttle to floor 5 times, ign off.

I also recall someone with a corroded wire on the crank sensor (rear of engine block drivers side).

Ian

[Bricol]

I'll second water down the plug holes - if its been stood in the rain, or power washed. 

Mines done it a couple of times over the last 18 yrs - always a surprise when the traction control cuts in on hard acceleration uphill from one of the junctions on my commute home . . .

[SM25T]

I had it last month after a long day on flooded roads. Water got in to a plug well hitting a flood at night. As the engine heated up, it boiled in the plug well and shorted out that plug, leaving the car on 3 cylinders.