Ok, I had noticed a slight random misfire at idle...but wasn't overly concerned, not yet.

 

However, a few times now from starting the engine (only noticed when hot so far), when I pull away the engine misses badly, only firing on 5 cylinders I think.

 

This only lasts about 20 seconds, then its fine (though the random misfire at idle remains).

 

This is starting to annoy me and I'm worried a bigger problem looms. I hate misfiring over all car problems.

 

I've just looked at the coil connections, they look ok. I haven't pulled plugs yet. This the first car where I've had individual coil packs for each plug, so this is new to me.

 

Are these symptoms familiar to anyone, could this be a PTU problem?

 

Cheers!

check all the coil/injector connectors they tend to get gunged up

Misfire problems can be attributed to a few things.

 

- MAF

- CAS

- PTU

- Coil packs

- Injectors

- Spark plugs starting to pack in.

 

Id start with cleaning the connections on the PTU, CAS and MAF, to check if its a coil pack, remove the coil pack plugs one at a time and then pop them back on, until you hear no chance in engine revs, this will be the misfire. then remove the coil pack and change it for one that you know to be working. If the problem then changes to the new location, its a Coil pack problem, do the same for spark plugs if it stays in the same cylinder. as for Injectors, get a long screw driver, put the tip on the end of the injector cap, put your ear against the handle, and you should hear loads of rhythmic clicking (engine needs to be running lol)

Cheers!

 

I'll go through all of those. I really hope its not an injector...

well as a indicator i've had intermitant misfires for a while it turned out to be injector connectors not only were they badly correded they all had the metal retaining clips missing so were either popping off or just the gunge causing bad connections, i've just replaced all my injector connectors and cleaned up the injector contacts, the zed is running very smooth now which it wasn't before

Should the injectors have proper plugs on the end of each wire? Mine look to be just spade connectors.

Hello Mate, Did you ever solve this?

 

Best, William.

Hello Mate, Did you ever solve this? - similar issues on my new 300!

 

Best, William.

Erm, sorry, nope.

 

I replaced the plugs, and listened to the injectors using the screwdriver trick (which isn't easy!), but sadly took the car off the road before I could solve it, as it was rotten.

 

My next step was the coil packs...

 

I have a new shell that I'm building, and I'll be using that engine, so I'll have to sort it out...someday. I have some spare coil packs, so once the engine is in and running, I plan to try different packs.

 

I know some people have replaced the PTU, which if I'm honest I'm not sure what it does, maybe manages the cylinder firing (anyone help fill me in on this?), but I do know that early series one units were faulty and recalled. I don't know which one I have, but the way my luck goes, it will be a series one.

 

Sorry I can't really help anymore with this.