My car keeps throwing code P0301 misfire cylinder 1. The DSC light also turns on and I can't turn it off. The car seems to run fine with no misfire that I can feel. Sometimes the DCS light will be off, then if I drive fast it comes on and stays on until I restart the car.

Fearing I have a burned valve, I did a compression check:
Max psi:
1 - 145
2 - 150
3 - 155
4 - 150

The JCW spark plugs look great and have less then 10,000 miles. I reinstalled them into different cylinders. I'm going to switch the injectors around too. So we'll see how it goes.

Anything else I should do?

I hope it's not the valves. That would freakin' suck, because this is my only car and is nearly impossible for me to pull the head off the car until January.

 

I wouldn't lean towards an injector issue, after swapping the plugs around wait for the CEL to return and see what cylinder is misfiring. After that I would swap 2 wires around and see if the misfire follows the wire.

I've seen more issues with wires than the plugs or injectors.

With those numbers I doubt you have a burned valve. The deviance from cylinder 1-4 is slightly higher than normal but they're still within spec.

 

I think I might have found the problem. I went to clean the MAP sensors and found that the T-MAP on the intake manifold had no rubber gasket on the plug. This allowed water to get in and corrode the connection. I'm thinking the gasket fell off when I did some work on the car last year.



The inside of the sensor also had corrosion in it.



I went digging around and found a gasket that fits perfect. Good thing I kept all the bits of wiring harness from a Crown Vic engine swap I did years ago. I'm going clean up the corrosion and replace the MAP sensors.

 

I have replaced the T-MAP and MAP sensors. The SES light is staying off. DSC system is acting normal too.

 

Bad news, the SES light and DSC light came back on today. It came on right after a warm startup. On the way home the engine stumbled for a second while in stop & go traffic, but runs fine otherwise.
I check the code, now I have:

P2300 - Ignition Coil "A" Primary Control Circuit Low
P2303 - Ignition Coil "B" Primary Control Circuit Low
P0313 - Misfire Detected with Low Fuel
P0301 - Cylinder #1 Misfire Detected

 

The coil codes may be from when you did the compression test and may not have cleared them. Swap 2 coil wires around and see if the misfire follows it to the swapped cylinder.

 

I'm wondering if any thing new came out of these new codes to fix the problem. I'm currently having the same problem with my Mini has the constant DSC light and can't figure it out.

 

It turned out to be a fuel injector. Everytime I move the suspect injector the misfire code follows it.
The P2300 and 2303 were from the compression test and never returned.

 

Thanks for the feedback, mine seem to stay with cylinder #4 after switching wires, plugs, and injectors. I also still have the DSC stay on with a slight sputter while driving.