[magpie197]

I have a 2000 1.8 zetec with a missfire on No 4 cylinder , engine management light lit up. I have replaced plugs and leads , coil pack and swapped 3 and 4 injectors to see if diagnostics showed diff cylinder. I have also carried out a compression test and all cylinders are fine. Would the next step be ECU and what is involved with this.

 

[iminhell]

Wow. Well if all that didn't change the misfire after clearing the code (hope you didn't forget that part). It could be the wiring for the #4 injector, noid light to diagnose that. Or it could be that you have an obstruction in that intake runner, have seen other cars where people forgot rags in things and gave problems.

It would be odd for the ECU to be the issue, IIRC there is only 1 ignition coil driver. So basically if the ECU where issue it would be an all fail or none situation.

Could also be an issue with the Crank Position Sensor.

When you pull the #4 wire do you see it sparking?

 

[magpie197]

The car is sitting in my lock up and i won,t be able to get back down there until sat. Yes i did clear code But i have,nt checked to see if if there was a decent spark from no 4 because i thought it must be coil pack so when i changed it and it was still the same i had to leave and go somewhere. Will check further on saturday when i go back down.