So I'm trying to tune my car and we can't get the motor to go over 7000rpm. I'm running a s300 with cpr. Motor is fully built(block and head) and should easily rev to 11,000rpm. All I can seem to think is the plugs im running are not right for my setup. Im running ngk v-power 4091. Our power goals are 675-700whp, anyone running this type of set up and ever run into this issue? Thanks

 

What is the actual part number on the plug? I am too lazy to look it up. What other ignition upgrades have you made? I had a similar issue a few years ago the runner and I thought that it was ignition problem and replaced everything and it ended up being a bad map sensor

 

The plugs I was running were ngk 4091's. We found the map sensor to be bad and also switched to a ngk iridium 6988. Problem solved and just for curiousity sake we made 641whp/388tq on 32psi! Thanks for the help!