Ruff idle....wont rev above 3000 At Times Codes 305. .316

Coil..wires..plugs ..have been tested and all are working..shop says compression in in bad shape...says cylinder 4 &5 are leaking 50-70% compression. ..worn valve guides.. Is this a common thing

They are saying because of 'worn VALVE GUIDES' it has poor compression??? I would recommend a shop DIAGNOSE IT. Burnt valve(s) maybe , by guides ........not compression related , would cause smoke issue. Cylinder leak-down or a standard compression test , if the valves themselves are not burnt/bent , they will not cause a loss of compression. Worn valve guides/seals , will allow oil into combustion chamber causing smoke. Good luck. I recommend a second opinion(or 3rd-after mine!).

This really frustrates me. I have brought the truck home I am or should say was a lic. Mechanic. But was in a bad crash causing physical and some Brain damage I have been out of doing the repairs 20+ years now..I think I will check the compression my self...I still have the tools ..I just need to write down what I have done.I keep thinking its a fuel problem.? I will check the compression first. . Any Ideas??

FIRST idea is , before spending money on parts guesses , since it is a 2005 and you got a misfire code for #5 , trace that down (spark/fuel/vacuum --?coil/plug) is the #5 plug oil fouled? , are ANY of the plugs oil fouled? Respond here , it might take a day or two , but I'll watch. good luck. IF you can get a scanner that will read live ENGINE data (should be less than $200.00 & well worth it) , that may be a BIG time and money saver!

I have not spent any money on.the truck other than the 500 I bought the truck for. The repairs coil..wires and plugs were all done by the prior owner in the last year. I would like to say thanks for all your help

IF all you got into it is $500.00 , I'd say it would be well worth getting a scan tool to read 'live data' !! But , definitely worth doing the compression test , remember the 'old-school' couple drops of oil , after the first try , if second reading goes up it's ring/cylinder problem , if no change , it's most likely valve (seat).Then , maybe get the scan tool.