OK, I am new to HP Tuners and somewhat new to LS motors. A little backround, I work for a restoration shop that sees a need for setting up LS motors for customers. Well I got tasked with the job to figure the wiring and tuning out on these motors. I am having some problems with my first motor. The motor is set up as a stand alone unit on an engine run stand. It is a 2004 5.3 DBW motor that we purchased complete with motor, PCM, TAC and Harness. The motor is 100% stock other than the air intake is Air Raid setup. I am getting extremely frustrated at this point. I am using a Corvette regulator and Warlbro Pump feeding from a 1 gallon fuel cell.
So here is what I am dealing with. The only things I have changed in the tune are, deleting VATS, and Rear 02's. I have eliminated some trouble codes I was getting. (mostly EVAP). The motor fires up well and runs pretty good in Open Loop. Once it warms up and goes closed it starts to idle terrible, and is running extremely rich. It idles up pretty good when you hit the pedal, but once it idles down it almost wants to die. To me it definitely seems to be air/fuel related. I am not sure if there is something else I need to eliminate in the tune that could cause this. When I say new to HP tuners, I mean very new. I don't really know what I am looking for while I scan. the code that concerns me is the P0300 misfire code I get. This code comes on everytime. When I leave the shop at night I disconnect the battery on the stand, so this is a code that I see everytime I start the motor. There are a couple others, like fuel level and oil pressure circuit, as well as quite a few transmission codes, which I expected to see on a run stand. The scanner is showing the misfires on every cylinder, not just isolated to 1-2 cylinders. I have searched for Vacuum leaks everywhere, and am on my second set of brand new o2's. (Long Story). There are no exhaust leaks. Everything I read is vacuum leak or o2's. I don't believe it to be o2's, haven't really 100% eliminated vacuum yet I guess. There does not seem to be very many places for a leak. The brake booster port is capped, and nothing else looks available for leaks. I did spray carb cleaner around and did not see any changes in fuel trims, which seem to be somewhat stable from what I can tell.
Tried so far
New Plugs and Wires
Checked all injector plugs with noid light and seem to be working as they should
New o2s
New Maf/IAT and checked wiring to the MAF which looks to be good
I have 50ish pounds of pressure at the rail at idle, but seems to be close to high 60s at idle. Return is unrestricted, I ran the open line back to the tank to make sure.
Coils seem to be firing
There has got to be something dumb here I am missing. I am attaching my tune and a short scan that I did. If there is something I need to scan that would be more beneficial please let me know. I m also going to attach some pictures of my setup to see if anyone notices anything out of the ordinary that pops out at them. Thank you for any help you can provide