I have a 99 Suburban that I put a 6.0 into. I got it running initially with the Stock fuel pump but couldn't get more that 40psi outta it. I replaced the pump with a larger one (quantum 340lph) and started it up. everything was logging good until i blipped the throttle pretty good then the Wideband went to super lean and maxed out on the gauge. I know its not lean bc I can smell the unburnt fuel. What would cause that? Maybe an exhaust leak opened up? Is there any way to read the o2 sensors voltage to see if they match the wideband at lean?
11-14 new fuelk pump.hpl