no compression in 5.4 3v p0301. very rough @idle and in OD

[MontanaRK]

Can anyone see an issue here? Changed plug, boot and much cleaning of valves but still misfire in cyl 1. Happened randomly one day and never cleared. Thanks

 

[Frank Wilson]

Mine looked like the red one. After further diagnostics they found a 30% blockage of the LAD.