Low compression questions.

So I have been trying to diagnose my truck. I have an 02 3.4l that has a CEL for p0305 and p0300 also p0420 and p0505. I tested compression and have 60 psi in 5 about 64 in cyl 2 and 120 in 4 the rest are around 180. The misfire is very minor. The truck still runs and idles fine. The only issue with the idle is when I start it cold motor it idles low like the engine is warmed up. Then once it warms up it idles a little higher which is weird but I doesn't idle or start rough or anything. Where should I go now with trying to figure this out?

 

Also I have already done new plugs wires and coils. Problem still persists.

 

take off the valve covers and check valve clearances. If all ok there do a cylinder leak down test to pinpoint where the air is going.

 

How many miles on your truck? low compression could be a few different things. Piston rings, valve adjustment, head gasket, cracked or warped head, etc.
Give the low reading cylinders a squirt of oil and test again. If the reading is higher than before, possibly piston rings. If it's valves or gasket, reading won't change.

 

I have 204k right now. And if I have 60psi is cyl. 2 and cyl. 4 is also low at 120psi wouldn't that most likely be leaky head gasket between the 2.

 

Completely possible, unless I misunderstood, you also mentioned low on cyl 5 also. Opposite side, maybe coincidence. If only 2 and 4, I would definitely suspect head gasket. I would try a leakdown test at this point.
You can also test antifreeze for combustion gasses. ( would verify head gasket) however, leak between cylinders may not contaminate coolant if it's not near coolant passage.
Ever have valve adjustment?

 

solid advice here. Would help eliminate valve adjustment being the cause

 

Ok yeah you are right cyl 5 and 2 both have about 60 psi but 4 next to 2 is also low at 120

 

And I don't know if the valves ever had adjustment I bought the truck from my uncle who is not knowledgeable in anything vehicle related. I doubt he ever had it done.

 

So I have an update I have done a second and third compression test and dripped oil down the low cyl. And the results were the same. So best bet would be valves then?

 

I would. It's a likely source of loss of compression and it could save you a lot of time and money vs thinking you need a head gasket, when maybe you don't.