Look in the business end of the connector and look for the numbers. Pin 6 would be the 6th pin in form the end, top row.

 

Well had a loose connection at the injector, after cleaning that up that same problem, did a compression test:
#8 90
#6 100
#4 112
#2 130

Did a wet test on # 8 and got about 10 more psi,(probley valves?) could this be the problem or

 

would these amounts be ok, as the truck ran fine a couple months ago , I also feel a vibration upon letting off the throttle at any speed.
Anybody have any thoughts before I have to tear the top end off.

 

your readings are really low except #2, i would double check them, checking if your spining the motor over the same number of times each cylinder ,IMO

 

Those readings are all over the place. Did you first warm up the engine before doing the tests? It doesn't have to be hot, but with these modular engines you just don't want it to be stone cold like from sitting overnight.

 

Ok did the test again warm and now have 60 psi on #8 the others went down like 20% also, what would cause the compression to drop with heat? Heads or cylinder/rings

 

Let it sit for 25 min - still warm and compression is back to 90 on #8 ? ?

 

Are you sure your getting the adapter tight in the plug hole?

 

Ya the tester is on tight, I've done this a few times and it seems like the pressure is up when cold and drops when warmed. Thinking mabye a cracked head that mabye opens more when hot.

Going to take head off and inspect, any tricks with removing head and or cam?

 

Found a good video on YouTube for head removal on a 03 navi, removed the head and found a burned exhaust valve on #8, cylinder looks good so am going to send it to the machine shop for a valve job - I'm sure this will be the fix!

Thanks to all who replied, I guess a simple compression check early on could have saved some time and money.

 

we had the same problem. replaced spark plugs, 2 new coils, opened checked backpressure, checked compression, leak down test. -only possible explanation was the engine computer ecu/ecm replaced ecu, reprogrammed, it worked. check out sacramento action car care 916-488-9600 sac, ca, 95825