Whenever I hit the juice (nitrous works 125 shot), the car will not rev over 5100rpms at all. It does this on any size shot; 50-150. I've changed plugs from ngk to autolite with no help.

Any ideas?

 

Will it rev over 5100 without the nitrous? Have you checked the rest of your ignition (opti, wires, connections, etc?). Also, what about bottle pressure? If you don't have enough nitrous going to the solenoids, then your mixture will go dead rich because of all the extra fuel being injected. Just some thoughts...

 

The car off nitrous revs fine over 5100 rpms. The ignition seems fine. The o2's also seem to be ok.

 

Do you have an aftermarket ignition? If so, what type & what is your plug gap?
This will tell a lot.

 

I've got msd 6a and autolites 104 gapped at .35. I've tried it with and without the msd. same results. I don't get it.

Could egr or header leak do this? One of the two are leaking.