Hey guys I have a 2001 GMC Jimmy I've had it for a year-and-a-half never had a single problem out of it until the last 2 months. It has developed a misfire under light load you give it just a tiny bit more gas and the misfire goes way runs great has power has new spark plugs and wires new cap and rotor ignition coil and ignition module and MAF sensor and new fuel filter. Yesterday I threw a code for the first time since I've had it it was a po446 I looked at the thread for it and checked all the stuff I need to and everything checks out fine only thing I haven't done is have a smoke machine ran on the EVAP system any suggestions as to what could cause my misfire but no check engine light

 

Did you use AC-Delco cap and rotor? Apparently Blazers can be very finicky about these parts. That, or the non-OEM parts are crap. Either way, use the AC-Delco cap and rotor if you have not done so already.

 

Everything is ac delco. Im big on replacing with OE equipment on GM