1997 Chevy Lumina code misfire

1 after you replaced all of those parts, did you clear the code?

2, is it a constant missfire that you can feel?

yes i clear them and they came back. the car feels like it has no power, and i did use, used parts but the wires are new. I replace the coils and the module. A few month ago I change the head gasket and it was running fine until now, I fallow my haynes manual to the tee the next thing to check is the timing belt probable not the problem, I now that using old parts are not the way to go but in time like this it's the only choice i have. when checking the crankshaft sensor i probe the back of the hardness with a voltmeter one to ground and the other to the return signal right and made sure there is signal coming in, put the ignition key to the on position and the motor not running, then i rotate the crankshaft, should i see a trigger on off signal meaning that the meter reads voltage as it turns, this is something i was not sure i did right because when i did it, I didn't see any voltage until it reach about a full turn that got me confuse. Wasn't sure if that was done right. After reading the manual carefully i believe that it should read the trigger on off signal as i turn the crankshaft (right), at least thirty on off signal per crankshaft revolution meaning one full turn depending on the manufacture of the vehicle. Thanks for the quick respond that's really appreciative.

I can not vouch for how to test the crank sensor, but if the book is telling you there should be that many signals, and you are not getting them. Then trust the book.

does it only happen after you start it, or does it happen during the whole drive to and from where you are going?

when you start it