Okay, I've been having a blast running the C4S with the cat delete pipes and the CEL on.

The one day I leave my car outside during a cold morning 40 degrees I take it out to go to work. Started accelerating on a straight away from stand still and gave it half way gas running to about 5-6K RPM's. Then the car just lost power and start running rough. I would try to accelerate and it wouldn't go any where.

I had the car towed home. Checked the codes and got random misfires on cyl 1, 2 and 3. I changed the coilpacks on cyl 1, 2 and 3 and tried to start up the car and it ran rough still. Then shut off and tried to start the car again but this time it wouldn't start.

2 days later, I tried again and it started up but really rough. I got a misfire code for cyl 4 and random misfire code. I have a new AGM battery. New AOS.

I replaced the coilpacks on cyl 4, 5 and 6 last night and tried to start up the C4S this eveing and the car is still running rough. No change in roughness. I am getting the P0300 random misfire code and misfires on cyl 1 P0301 and cyl 6 P0306.

I have been reading about the camshaft position sensors. I used to have a BMW E39 a long time ago and it had the same rough idle at start up one random morning. I replaced the two camshaft position sensors and it purred like new again. Zero issues afterwards.

Anyone, have the same experiences? I want to order two camshaft position sensors but couldn't find any do it yourself. I found this camshaft position sensor location on pelicans site but the close up is too close for me to understand where exactly it is and how difficult it is to get to them.

Can anyone help?

 

Hope you did not hit 5-6K RPM's with the engine cold on a 40F morning.

You changed the coils but what about the plugs? Are they reasonably fresh? Of the right type?

You sure you got all the coils secure on the plug and at the wiring harness connector?

If the cam position sensors are bad then they both went bad at the same time. Not likely.

Besides if one sensor or both sensors were bad there should be at least one error code flagging one of the sensors. Now the code might be a pending code. The DME can adjust fueling to try to the expected O2 sensor readings it wants to see and if the fueling adjusting goes too far one or more cylinders can misfire. The misfires generally have the driver parking the car so the cam position sensor error doesn't become active.

How old is the fuel pump? If the car is equipped with a serviceable fuel filter have you replaced this on schedule?

Any work on the engine recently? Perhaps you disturbed a hose or in some way introduced a intake air leak? Cracked the oil filler tube?

 

Checked all the coilpacks and made sure they were clicked on all the way. Now the misfire is only on cylinder 1. To rule out a faulty new coilpack I bought two more new ones. Put it in and still misfiring on cylinder 1.

I took out the spark plug in cylinder 1 and found the plug to be fouled with fluids either gas or oil or both. I put in a new spark plug just to test and same thing start up idle was rough and then gets worse and then the CEL comes on and starts flashing.

Anyone have any ideas what could be causing the spark plug to get fouled? The picture below is the new plug that was in cylinder 1 for literally less then 30 seconds with the engine running and got that dirty so quickly. It is side by side with another new plug. Any thoughts?

 

Both new plugs. Dirty one was only in the car while running for less then 30 seconds.

 

Original new fouled plug in cylinder 1. This is also a fairly new plug when all 6 plugs and coilpacks where replaced.

 

I don't think running with the CEL on with the cat deletes helped. Probably won't do any good now but plan on putting the cats back on and the factory intake as well....

 

Is that oil on the plugs? Looks like oil, fuel would have been evaporated off by the time you took the photos. New AOS? Is there oil in the intake? Are you getting any piston noises?

 

I also see never-seize on the plugs, NGK and Porsche say not to use it. But probably not the issue here.

 

Wow..that looks like a lot of oil on those plugs, bad AOS, something is not correct there. Also, are you using champion plugs? If so that could be the issue, but you still need to clear up the oil problem.

 

Yeah, looks like oil and fuel. I got some platinum champion plugs for testing. They fouled heavily in less then 30 seconds of rough idle.

New AOS $800 labor and $119 part. Is it possible that it was defective?

 

Idles so rough if there is piston slapping its drowned out by the rough idle.

 

What do the other plugs look like? With only one bad cylinder it should be idling too terribly rough. You would be able to hear a scored cylinder over the misfire.

 

i had similar problem on my 03c4 cab, a friend told me to run some fuel system cleaner after i changed #1 coil . car ran great after that

 

Well, first while the plugs may not be the problem why you moved away from the 4 ground electrode to the single is beyond me. I'd install the right plugs not what some possibly goofy reference chart offered.

Next be sure the coil is connected securely to the plug tip and the coil is properly connected to the engine wiring harness. You probably should remove the coil and carefully check its connector and that of the harness to make sure all pins are present and none are bent or one is broken off in the connector's socket.

If all looks ok then install the coil, a new plug -- do *not* use anti-seize -- and road test the car. If the missing comes back suspect a bum coil. You can try swapping coils to see if the behavior follows the suspected coil or stays at the cylinder.

(If you have used anti-seize this can and will contaminate the O2 sensors and these should be replaced after all the plugs are replaced *sans* any anti-seize.)

If bum behavior stays at the cylinder you could suspect the fuel injector. The tip is contaminated and the spray pattern is horrible or the injector is leaking. In this case the fuel trim on that bank would be moved to the lean side which could have the other good cylinders misfiring because they would be running too lean, so I do not think the injector is leaking but you need to make sure.

 

Man, just bought 4 new O2 sensors and still the cars had a flashing CEL. For the less then 15 secs of run time before the car dies I pull up 3 CEL codes misfire codes for cyl 1 and 4 and generic misfire overall.

So far new MAF, 8 new coils (2 additional thinking it was cyl 1 only), 4 new O2 sensors.
One thing I did ignore are the spark plugs because they were newly installed on my last service along with the new AOS and 1 new O2 sensor.

After learning more the plugs are probably fouled from previous running rich conditions. Going to swap out all new plugs temporarily with the Champions and see if the car will at least stay running (currently dying and have to wait hours to try to restart).