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??