03 Ram 5.7 Hemi problems.

If the spring breaks and the valve floats and lets a retainer go and drops the valve then it will barely run, but if the spring is just still broken but intact it might just intermittent misfire until it does let it go. If you catch it early it is a much less expensive fix.
Our 08 5.7 had a bad coil not firing one cylinder at all and you could hardly tell it was missing. By 2008 they don't cross the wires anymore so when a coil goes you don't get either plug firing in that cylinder. Luckily it did throw a code and $32 and 20 mins later it was fixed.