i bought a 2005 dodge ram 4.7 liter about 3 months ago it ran great and then 40 miles after purchasing it it started to loss power and after 10 to 15 seconds it would clear up and run great the remainder of the drive
and so we hooked up the modus to it and it was reading misfire . i replaced all the sparks plugs and the ignition coils . the truck still misfires and is getting worse and worse
when i take off the truck falls on its face and has very little power then kicks back in . it usually only does it right after starting it . doesnt matter if its hot or cold . every once in awhile it will do it at a stop sign to
not sure what to do from here. any help or advice would be greatly appreciated as i cant afford to put it in the shop but can do the work myself.

 

Post the codes ,,and check fuel injectors as they can cause the misfire and poor running

 

po308 is the code its throwing . someone told me yesterday that it could be a clogged fuel filter the truck is from the coast so maybe there is sand / salt water in the tank. could this be the issue and would the symptoms make sense for it to be a clogged fuel filter?

 

That code is for cylinder 8. Fuel issues from the tank tend to affect all the cylinders. I'd swap the number 8 injector with another and see if the codes follow the injector. If it doesn't, time to do a dry and wet compression check - and look for evidence of antifreeze where it shouldn't be (crankcase).

 

now its throwing a 300 code random misfire and my coolant has went down about half way my buddy seems to think its getting coolant onto the cylinder would that make sense?

 

Possible, and that would likely indicate a head gasket seal issue. I would perform a test that is conclusive before ripping into it, because that is not a quick and cheap repair. There is plenty of internet instructions on how to test for a blown head gasket.

 

Sounds like a leaking or blown head gasket. Those 4.7's were also known for bad oil sludge.

 

With it being cylinder 8 i would almost bet money on it being a dropped valve seat. Hope thats not the case for you.