misfire piston 7 miles on truck 52.000
How do you know its #7? Also, what engine?
I’d start by removing the coil assembly on #7 and switching them to another cylinder. Does it now misfire on that cylinder? If Yes, replace the coil.
No? Remove the spark plug on #7. Does the plug look oil fouled? If Yes, run a compression check on all the cylinders and check each plug for oil fouling.
If No, replace the plug in #7 with a new one. Does that fix it? If Yes, buy 7 more new spark plugs and change the others.
This has a good chance of fixing it but report back if there is more than one plug oil fouled.