Need help p308 code 03 cobra

[How2003cobra]

Hi

I have a 03 cobra orig owner and stock. 77k miles. I had a p308 code. Changed plugs moved the coil to Another cylinder. After Erasing the code. I ran the car hard and it ran well. As soon as I got the car in the garage the p308 code came on.

Need help please

Thanks

 

[hotcobra03]

Does the connector clip on tight?
And stay with gentle pull on harness ,,

Think some others have had issue on engine harness main connector by fire wall..

Just something to look at since doing a swap already

 

[How2003cobra]

Thank you will look

 

[decipha]

most likely a weak fuel pump or a bad injector

slim chance but could be a leaking valve seal. Usually they set a fault on cold start though after sitting a while with noticeable instability.

 

[01yellercobra]

I was going to suggest moving the injector next.

 

[How2003cobra]

Is there any way to check the injector Also how hard is it to replace and do I have to replace all 8

 

[Roush6018]

you have a misfire on the rear cylinder which is known for running hot. please take the spark plugs out and do a compression test on all 8 cylinders , cold motor is ok, warm motor will give better compression readings. if the number 8 cylinder has over 15% compression less than the other cylinders , there is a problem with the 4 valves in there or the piston has a problem (it would be a more obvious misfire if it was the piston) if only one of the valves failed it will cause compression loss.

i think the injectors are ok and i think the coil packs are ok up untill 100k miles.

dang i feel bad for the owner too having to drive a stock cobra, its what we have to do to stay registered now days! at least that supercharger still whines at stock boost!!!!!

 

[How2003cobra]

Ok thank you

 

[01yellercobra]

Is there any way to check the injector Also how hard is it to replace and do I have to replace all 8

Just move it to another cylinder like you did with the COP and plug. If the code follows you''ll know. You might be able to get away with just getting it cleaned. I would do all 8 if it came to that.

I'll add my own anecdote. Shortly after I got my car it started to get a miss under boost. It steadily got worse, but never showed up under part throttle. And it was never enough to set a code. I ended up swapping the COPs out for a spare set I had in the garage and it's been fine since.

 

[How2003cobra]

Thank you