I have had to start driving my Tahoe because my Suburban is down, so now I have to break down and fix my tune in it. It's my 99 Tahoe with an L31 5.7l vortec, marine intake swap, 0411 PCM swap, no EGR, and 75mm throttle body. I've had issues with it since day 1, but with alot of help from here, it's at least driveable. From day 1 I've had problems with it when cold running in open loop, it wants to stall when you give it just a little throttle.

For those not familiar with the 5.7l vortec, the stock throttle body necks down from 75mm to about 69mm right under the throttle blade, and they have an air foil mounted on them that basically makes only 1 side of the throttle blade let air in until about 1/4 throttle. I'm running a 454 throttle body which is a straight 75mm bore with a flat blade, so at low throttle it lets in considerably more air much faster than stock did. With alot of help in this thread https://forum.efilive.com/showthread...le-body-tuning ,the off idle response has been good, but when cold giving it just a little throttle it wants to stall.

After finally getting my wideband installed I found when its cold in o/l, Ive seen it go as lean as 18.7:1 so far, and it hasn't even been cold out, so I'm pretty confident my issue is a lean mixture when cold, and I have a feeling it goes back to my throttle body that lets air in so much faster than the stock one did. I'm getting ready to try and do some logs to correct my VE table, but is there any other tables I should look at for this extreme lean condition when cold? I don't think my VE table is that far off because my fuel trims are normally within 0 to 3, but my wot afr's are running 11.6-11.8:1, so I know it needs a little work. I'm just at a loss here coming from diesel tuning to gas tuning.