Misfire when cold P0304

Nathan_McCurdy

Hello Guys

I am new to the forum and need some advise with my Z22YH engine. When i start the car from cold i get a intermittent misfire on cylinder 4. When I use scanner to clear code engine idles smooth.

I have changed the plugs and coil pack and for the first 2 days after it started fine then misfire came back again.

Then found out that my fuel pump died and was not producing enough pressure so i changed that, it had the newer continental pump on so replaced for a new Conti pump and all was fine but still have the misfire.

Can anyone help point me in the right direction as to what my options are next.

Thanks in advance

vocky

cylinder 4 misfire will either be the spark plug or injector, might be worth swapping them with cylinder 2 and see if the fault code moves to P0302

Nathan_McCurdy

vocky said:
cylinder 4 misfire will either be the spark plug or injector, might be worth swapping them with cylinder 2 and see if the fault code moves to P0302

Thanks for reply vocky

I have had the injectors swapped and code still came back on cylinder 4 and as said plugs and coil pack been changed. Is it worth trying to swap the plugs around to see if it the code moves.

vocky

it's worth swapping the spark plugs between 2 and 4, if it stays on 4 then it could be the injector wiring or still the coilpack.

Worst case would be a burnt valve, easy to check with a compression test.

Nathan_McCurdy

Ok thanks vocky.

I will try swapping the plugs as is easy enough. I have changed the coil pack twice.

Burnt valve that sounds expensive lol.

I have had the head reconditioned so all valves lifters etc have been replaced. Skimmed and de choked.

Question I have is why would it misfire on cold start but once code cleared it drives fine all day?

ob_one

had a similar problem with my car when its misfiring try pressing down on map sensor