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CT 525, #1 cylinder shoots 200-250 degrees colder than all others with heat gun and motor pops and cracks between 2500-3000 rpm,,have changed msd box, wiring harness, coil pack, plug, plug wire, checked compression (150 lbs), took valve cover off and both valves are moving, valve springs look ok,,changed crank and cam sensors,,,checked header for crack,, any ideas?? Checked #1 plug and it is firing
Sounds like it is just misfiring between 2500-300 and clears up and runs ok in higher rpms?
Have seen weird stuff from the LS MSD boxes before. I assume that you moved the coil pack from #1 to another cylinder to see if that moves the miss ? Intake runner vacuum leak on #1 ? #1 plug look the same as the others after racing it ? Misfires are compression ( rings/valves ), fuel issue ( usually with injectors ) or a timing issue.
What msd box do you have? It it's the old 6010 or 6012 scrap it for the new 6014. They allow individual cyl co trolls for timing.