Hello everyone. Needing some help in major way. This started coming home from work and I was driving at 75 and I heard a miss from engine. Well it would rough idle at stop but at highway speeds smooth out. Well I went to work next morning thinking I just needed a tune up. Well it got so rough that the truck would die once stopped. I got home today and pulled all plugs and they looked good but #4. They had oil on them but it wasnt wet but dried up. Its was the only cylinder that had this look. I got the P0172 code also. Im thinking broken valve spring? But please tell me its just bad injector or coil please. I changed all plugs and wires. Havent done the EGR yet. I dont want to drive it anymore and drop a valve if spring is broken.
Note on test drive I got the little lighting bolt on dash pop up for a sec and another p0172 code. It will not idle with help of touching the gas.

 

My oppion would tell you to change the Crankcase sensor.

 

When my EGR went out on my old 2004 it would lose all power and start completely cutting out at low rpms just cruising around town at about 30 mph. Doesn't seem like the same problem you have. Sounds more like timing or ignition issues. I would think you could hear a broken valve spring or valve problem very easily at idle. Just my guess but good luck.

 

Nothing sounds broken. How would cranksensor cause such a rough idle? Wouldnt it give a code if bad. I mat just try egr in morning. It cheap enough. Anything else to look for.

 

My first thought is a broken valve spring. Only one way to find out

 

Broke spring on #4. %Damn