This problem has definitely gotten worse this past winter so I am paying much closer attention to how the engine is running. I noticed that the engine runs rough around 2400 RPM with the transmission in park. There are more air bubbles running through the clear lines at this RPM especially the 2 lines on top of the fuel shut-off valve. While driving and keeping the RPM around 2400 and can feel a slight droning type vibration as well.

Also now that it’s getting warmer outside the engine takes longer to start when warm. This doesn’t happen all the time, but definitely getting worse.

So I decided to replace all of the clear fuel lines and the 2 black fuel hoses that go to the tank because they are old and showing dry rotting. Every hose I removed I inspected the o-rings and bore that it goes to for any evidence that could cause an air leak. I found 2 things that caught my attention. The green o-ring that goes on the bolt for the banjo fitting on the clear line that goes to the back of the IP was cut. The other thing I found was after removing the electrical connector to the fuel shut-off valve there was fuel inside of the connector, but not leaking out of the connector because there is an o-ring holding the fuel in the connector. I was hoping I had found the problem so I replaced the fuel shutoff valve in addition to all the fuel lines previously mentioned. I ran the engine with the IM removed and the air bubbles are still running through the lines but much less and the engine still runs rough at 2400 rpm.

Now I decide to do a compression check on a cold engine. The gauge I have is 350 psi max so when it reaches 350 I stop cranking. Here are the results:
#1 – 280 - took 10 seconds of cranking to reach this
#2 – 350 – took 10 seconds of cranking to reach this
#3 – 350 – took 7 seconds of cranking to reach this
#4 – 350 – took 7 seconds of cranking to reach this
#5 – 350 – took 7 seconds of cranking to reach this
#6 – 350 – took 7 seconds of cranking to reach this

According to the numbers Diesel911 sent me it appears all cylinders are within limits but the difference between cylinders fails.
Note: the procedure he sent me calls for a hot engine not a cold engine

Another thing I noticed is lots of oil in the 3” intake pipe that connects to the IM. I have always noticed this and never paid much attention, but it seems more than usual.

At this point I’m going to put the IM back on and drive the car for a while hoping for improvement but expecting the same. I know there are still some air bubble in the fuel system but that #1 cylinder concerns me.