I cannot get a misfire code to throw on my truck. Running 2003 stock ecm with hptuners and the 3 bar os upgrade. Ive been chasing a nasty misfire on my truck, but I cannot get it to throw a single code. Ive gone as far as unhooking plug wires, and still shows nothing. Is this just not available with a 3bar? How are you guys diagnosing a misfire with a 3 bar os?

 

Solved! Just incase anyone is wondering, misfire detection is not available in speed density. The maf has to be enabled.

 

I get an occasional P0300 code, and I'm running a 2bar semi-open loop speed density tune (EFILive COS 5).