# VG30: Miss migrates from cylinder #1 to #4



## filo (Dec 16, 2010)

I have a VG30e in a 92 pathfinder and it's running very rough. 

I started by checking for obvious vacuum leaks and found none.

Then I removed plug wires until I found one that made no difference. Cylinder #1 was the culprit. I saw spark when I placed the wire against a ground source. Replaced that plug but still saw no difference whether the wire was on or off of the plug when idling.

Next I replaced the #1 wire. Still the same thing, spark at the wire, but no difference if it was on the plug or off.

Next I replaced the cap and rotor. Still the same thing, spark showed up on the #1 wire but it still missed. 

Next I replaced the distributor with a spare. As I was removing the distributor the shaft spun and I lost track of which direction the rotor was pointing (haha). When I put in the new (used) distributor I guessed at the orientation. The truck fired up and after adjusting the timing a bit it ran just like it did before (still rough).

Next I checked the #1 plug wire again and removing it caused the engine to really stumble(!) So I went through and checked the rest of the wires and now #4 was doing the same thing as #1 before. 

I checked for codes at the ECU and got a 55 (no malfunction detected).

I at first was starting to think the #1 fuel injector was not firing for whatever reason. Now I'm confused. Changing the distributor caused the problem to move to the #4 cylinder. This rules out a mechanical injector problem to me.

Does #4 fire when #1 is at bottom dead center? Could it be that I installed the distributor 180 degrees off and for some reason the computer is not firing the injector on what it thinks is the #1 cylinder?

What could cause a spark or (more likely) fuel problem to move from the #1 cylinder to the #4 cylinder like this?


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## rogoman (Dec 16, 2004)

The camshaft position sensor that's built into the distributor may have a problem. Not sure if it's serviceable by itself.


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## filo (Dec 16, 2010)

That's what I thought, but after replacing the distributor I still had one cylinder missing. #4 is at TDC at the same time as #1, right? So if I had rotated the distributor shaft 180 degrees the ECU would think that #4 was #1, right?

This is a strange problem.


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