2002 996: had the IMS done, engine failed at 75K believe it was a cylinder, no compression anywhere, ended up getting a mustang GT (this lasted 6 months) now back in a 997.2 :-)

rkat is idle trims, measured in %; out of spec is anything outside of +/- 4%.

fra is low load trims, measured as a numberic deviation around 1; out of spec is anything outside of 0.7 to 1.32.

as stated + % or over 1 is adding fuel, otherwise taking fuel away. trims are a result of dme determining how combustion is going via the o2 sensors - intent of trims is to address failing/aging components (air leak after maf sensor, injectors going out of spec, etc.). so if injectors are clogged computer will try to add more fuel to compensate and this will show up in the trims. note o2 sensors only work in a low load situation; in a high load situation computer adds addnl fuel to cool engine howver results go unmeasured as o2 sensors dont work for this richer air/fuel ratio. bad injectors can result in engine running hot, which causes detonation, damage, etc.