need some help please

[ace_1_dawg2008]

i got a 99 gmc sierra 5.3 it idles find but when u lay into the gas it skips at about 4 grand checked plugs and wires change fuel filter put it on a obd2 and it says bank 1 lean and random misfire if ya know anything let me know

[maxwedge]

Welcome to AF, start with checking fuel pressure, look for 60-65 psi, I assume you are not gunning it in neutral, correct?

[ace_1_dawg2008]

yeah it does fine in park and all but some times it will do it and some times not
i bypassed the egr and put headers and had the cats cut off about 2 months ago is kinda acting like its a clogged cat