bad surging problem

[silveradorider04]

I need help guys. I have 04 Silverado 5.3, bbk 80mm tb, underdrive pulleys, gm lsa cam 226/236 525/525 110lsa, 8.5 msd wires, tr6 plugs, 1 3/4 long tubes 3" y-pipe, 3" exhaust into magnaflow race series muffler, electric cutout, vette servo, 3200 circle d stall. Truck has been running fine. Recently started surging during braking slowing down. Surging to the point I am shutting down at red lights and pulling into parking lots. Thought vacuum leak was culprit but after pulling off and checking seems to be fine. Torqued everything back down. I am lost any advice would be welcome before I drive this thing into light pole.

[farmtruc]

If it was running fine before, then the best thing is to start diagnosing it, I would start with a vac leak; of course you already did. Do you have access to a smoke machine?
That's the quickest and surest way to determine a vac leak.
See if there are any dtc's.
Check o2 sensors, make sure they are operating correctly., the ltrims will give you an idea.

[silveradorider04]

no dtc's, don't have access to smoke machine. Wish I did though sure would make life simple. I will check the o2 sensors next. It's surged and stalled before but nothing like this. Just out of blue every stop revs up drops down revs up drops shuts down. Thanks for input Allen.

[farmtruc]

Anything loose on the intake air tube?

O2's should be toggling up and down between 50-900mv's

No problem. Good luck

[silveradorider04]

I still haven't checked the o2 sensors but stopped at store shut truck down and came out truck just clicked. Ended up finding bad ground on battery. Ground corroded and seized into battery. Guess being I have had same optima battery since 08 lol. The battery also has top posts so rerun grounds and for time being the truck has settled down a lot.

[silveradorider04]

Allen hey buddy finally watching o2 activity since truck started acting stupid again. Surging wanting to shut down. Throwed random misfire code today. O2 readings show 0.900-0.940v

[96/chevy/pu]

Sounds rich, are the plugs black?

[farmtruc]

pcm may not be going into closed loop for some reason, possible o2 issue or misfires.

[silveradorider04]

Smells rich plugs was a little black, not very bad. Changed from a/c delco iridium to ngk tr6. Changed air filter as well. Smells like old fuel when running. Beats the hell out of me. Truck had issues when 1st did cam swap with the infamous gm asa cam. Tuner flew into atl I met him there we rode tuning for about 2 hrs until it was perfect. Now truck is back to same ole crap.

[silveradorider04]

Tuner said something bout having to use a rolling idle. Idk I leave tuning to experts