Fault code 16688 Misfire 16804 Catalyst System Efficiency Intermittent problem

[Will-Hickey]

Hi, I have had for a long time the emissions light coming on for small amounts of time and going off however recently it has been coinciding with a significant loss of power under acceleration and flashing not every journey though and only very intermittently. More recently it has gone into limp mode twice with the EPC light coming on, once you turn on and off though it resets and the lights disappear.
Finally got a working diagnostics tool on it and read codes:
16804/P0420/001056 - Catalyst System; Bank 1: Efficiency Below Threshold
16688/P0304/000772 - Cylinder 4 Misfire Detected
16684/P0300/000768 - Random/Multiple Cylinder Misfire Detected

Does anyone have any ideas the best path to rectify this and are they likely to be linked, iv'e read about people changing coil packs to fix the misfire code but don't see how that would affect the cat

Taking the car on a very long journey in a few weeks so needs fixing asap!

Thanks!!

 

[SwinDan]

Sounds to me like the coil pack in cylinder 4 start there and the cat problem should go away if the engine isn't firing correctly the cat doesn't work properly not enough heat generated in the exhaust

 

[SwinDan]

I would probably change all 4 while you have it apart because as soon as I changed 1 another went so saves time in the long run easy job even for the non technically minded

 

[Will-Hickey]

thanks for the advice i'll try that, i cant do it for a week or so do you think ill be harming the car driving with it?

 

[RUM4MO]

Tricky question, the car engine system is reporting there is an issue with the cat, it sounds like there is possibly an engine issue that is causing the cat to fail to perform as intended, if you poison the cat it might not recover, so more money down the drain possibly if you continue to use that car prior to getting it fixed - but in your case, lots more money might be out weighed by inconvenience of not having a car, your shout?

Edit:- I checked your profile but you have not listed exactly which model of Ibiza SC you have, ie engine type/size, maybe add that info into this thread.