Engine stalls while driving down highway

If you have no compression, then you have to have a valve open at the wrong time. Even if you had a bad head gasket, bad piston rings, or worn cylinder walls, you would have some compression.

With that, you need to remove the timing belt covers. Once you have access to both cam shaft pulleys, first place the crankshaft pulley at TDC. See pic 1. Then confirm that the cam timing marks are aligned Pic 2. You may have to fully rotate the crankshaft a few times for them all to align, but they at some point must align.

In the last pic, I circled the cam gears.

Now for the bad news. If the timing has jumped, there is a good chance internal engine damage has occurred. The 4.7 is an interference engine which means there isn't enough clearance between the pistons and valves and they will hit if timing is off. If you determine that the belt has jumped, the next thing to do would be remove the affected cylinder head and check for damage.

Let me know what you find. If you determine you want to replace the timing belt, I will provide the directions as well as cylinder head removal.

Joe

Crankshaft sensor cannot cause no compression. That is either a bad cam or timing jumped and now valves are open when they shouldn't be. To add to what Joe said, see if you can get a leak down tester. It allows you to put air into the cylinders one at a time with them at top dead center. The valves should be closed and the piston all the way up, then you lock it so the crank doesn't move and apply air pressure through the spark plug bore. Now you listen for where the air is coming out. You will normally hear some coming through the dipstick tube because air will get past the rings but it shouldn't be a lot. Now the valves should be closed at this point so if you hear air through the intake or exhaust that is where the problem is. Do all the cylinders that have no compression and see what you find.