Ok Long time reader first time asker. I have an 04 F-250 6.0l Power stroke diesel with a problem. The engine starts fine and runs normally until it gets warmed up. Once it is at normal operating temperature it starts to sound like it is misfiring when idle. Once I accelerate it sounds normal again but when I slow to idle the misfire comes back. Any suggestions that won't empty the bank account?

Thanks.

 

do you have a Gauge to monitor sensor Values? like Scan Gauge or IPhone app, dash boss etc, we need to look at some numbers of= ICP, ICPV, MAP, EBP. for starters, again 1. Injection control pressure 2. volts from ICP 3. Manifold Absolute pressure, 4. Exhaust back pressure. or you could try a wiggle wire harness test with engine running , the ICP is on the passenger side valve cover, the connection will short out at hot temp before it plugs into the sensor, also look for oil on the sensor and connection

 

Ok Thought I would add an update finally as I have found a good mechanic. I had one bad injector that was replaced in cylinder 5 and ran scan for codes. Still having an issue when Idling not quite a miss fire in cylinder 4. When the fuel pressure is pushed up a notch with the scan tool the rough idle goes away. Also when accelerating and under throttle all cylinders are running normal. Wondering if it is another bad injector or ICP sensor.

 

Make sure fuel pressure is above 45 psi always. Do the blue spring upgrade if it isn't done, that will bump the pressure near 60-65psi. Lower pressure can damage injectors. Something that really can't wait, especially if your having issues that go away by increasing pressure!

After the scan gauge is installed or your mechanic, check FICM output voltage, need to be at least 45v. Normally this would increase as temp increases, still worth checking.

Truck will run with a bad ICP, just not great. Unplug the sensor and see what happens. You will get a CEL because of it, won't hurt anything and will clear once you plug it back in and clear the code.

 

do you mean the ICP pressure? you cant change fuel pressure with a scan tool

 

If you increase the idle speed it ups the icp pressure. From the replies and a little research I think my problem is most likely injector 4.