I really hope someone has had this problem or at least has a solution. I just installed a NOS NOSzle system, MSD plug wires, AEM fuel rail, and a walbro 255 lph fuel pump in my GSR. Since installing these my idle has been strange. It fluctuates between about 1250 and 1800. I also installed A/F ratio and Fuel pressure gauges at the same time. Fuel pressure doesn't seem to change much, about 42psi unless I am really on it it goes to about 55psi A/F gauge bounces like crazy unless I am WOT, is this normal? Is this caused by using the stock FPR or could it be another problem? I checked for vacum leaks but I might have missed something. I would really like to test the nitrous but I want to fix this problem first!

 

what kind od A/F guage is it?

with the bigger fuel pump i would say that ur getting too much fuel...

 

It is an autometer gauge, it bounces with the idle but it does it while I am driving also. I have heard that this could also be a high idle valve problem?

 

ive had problem before where my idle fluctuates just like yours and i figured that it was the fuel pump running too rich...try to take them off and put the stock pump and see what happens...but dont run the car to WOT..just let it idle

 

whats the guage reading when ur at wot at 2000 rpm/? with a biger pump and no tuning, best bet is that ur running rich ...

p.s. autometer guage sux, not accurate... just colors going back and forht.. doesnt only give u an exact number..

 

At wot at any rpm the gauge reads almost to the extreme of rich, otherwise it jumps from extremely rich to really lean and back. If it is over fueling how do I fix this? FPR? AFC? I live probably 300 miles from a decent sized city that would have a reputable tuner shop. I'm kinda on my own out here.

 

afc and dyno tune