I have 03 ZO6 with mods in sig. Shot is 150. I have been having issues with the Nitroius cutting in and out at 5000 rpms or so and above. I have MSD Dig. window switch, FPSS, WOT Switch(under accelerator). I thought it was fuel pressure so I upgraded intank pump to Walbro 340M(255L). Went to track yesterday and still having issues. I had no issues on dyno. The car doesn't feel like it is starving fuel because I would expect the Nitrous to hit pretty hard until the fuel pressure drops too low. Almost feals like it is bogging. I do not have a electric Fuel pressure gauge, only gauge in engine compartment. I am planning on getting a incar gauge but what else should I check.

Thanks in advance,
Jim

 

i would still bet fpss. just by pass it and see if it fixes it. we never use them. if all other safty switches are working it will be ok. the stock style fuel system takes to long to recover and it can make the spray palse and cause the FP to seesaw .

 

I think I will give it a shot and see what happens once I get the fuel pressure gauge in.

Thanks much

 

im pretty sure the problem is the fpss. ive turned it down but cant get any nitrous(everyone is out) to see if that eliminated the problem.