Strange misfire on cold engine
 

Lads having serious problems with my ZS. For the first 5/10 minutes of driving when I let off the throttle the car misfires and splutters like mad. It hesitates really bad under harsh acceleration. This goes away after about 5/10 minutes and then the car drives fine, no loss of power and no misfires at all. Another thing for the first 5/10 minutes the idle is around 1100 RPM even at normal operating temp. It used to settle to around 850 after 5 minutes until this problem came up. Its a 2005 ZS 120 1.8. Have recently changed plugs, HT leads and coil packs along with a fresh fuel and air filter. No fault codes what so ever and no EML. Swapped crank, cam, throttle position and MAP sensors for known good ones and still no joy. Any ideas on where to go next?

our postmans wife has a TF, he was saying the other day it had the same symptoms from cold. Rough running and loss of power.

They called the AA out and it turned out to be one of the sensors in the exhaust, I think. The AA guy said it would OK if they let it warm up before driving off.

He bought a new sensor and their son fitted it and cured it.

If I see him I'll ask what one it was,

just seen the postie on the dog walk.

He says it was the lambda sensor, in the exhaust and reads the Oxygen % ??

http://forums.mg-rover.org/mg-zr-rov...sensor-445309/

Update getting a EML flashing with the code P0300 random/multiple cylinder misfire detected

I had the same problem on my ZR160, changed the coil packs for new ones and the problem went.