Ok, now I'm really confused:

My CEL has been on for a long time and last time I jumped the codes they were 71-74 (I think). I believe this is due to the spec b's I'm running now.

Weird thing is I didn't drive the car for about 5 days and next time I start it up I don't have a CEL anymore? (I didn't reset it either!)

Well, does it reset after a while or what?

And then after driving for ~20 min it came back on?

This is just too weird. Someone please offer some explanation!

Oh yeah, supposedly another guy on this board had a cel and reset the ecu and then his whp jumped up by ~10whp on the dyno! WTF? What codes pull timing or otherwise rob you of whp?

 

after a certain number of "driving cycles" if it doesnt detect the problem it will
store the code and turn off the light.

regarding the jump in whp, that was probably to due long term fuel trim and
not the MIL.

 

some codes put the vehicle into a limp mode until repaired, that would cause a lower whp

 

not exactly

that limp mode will give you a rev limit of 6000rpm
or the car will not run in limp but will behave very strangely due
to the lack of a sensor to which the MIL is related. But drivablility would be
affected as well.