I recently put on MAC Headers with ORP. The first two weeks I was running without o2 sims, and this past week I got them and put em in. Before, my car never used to pop really bad at all(w/o simms). Ever since I put them in it pops A LOT. (For ex:1st gear punch thru 3rd then let off, pops a shitload). Do the o2 sims tell the computer do just dump a shitload of fuel or what did they change to cause so much popping?

 

TTT

 

The O2 simms only tell the computer that your cats are working. If your cats "malfunction" it sets off the SES light.

Some cars run rich with headers. You can use ATAP and measure your O2s to verify you're rich or you can try some ported MAF ends which will lean the car out.

Check your primary O2 wires and make sure they are not damaged.