5.3 Tune - Engine Has Several Mods

[BillCham]

Hello-

A VERY new Newbee here.
Trying to get a base tune on an engine so that I can hand it over to a tuner to get it 100% right.

Some info -
2004 5.3 GEN 3 cast iron truck motor.
bored to 5.7
CAM - 275/277 seat duration, 222/224 duration at .050? lift, .566/.568 lift, and 112 LS. matching springs/retainers
10.5 compression
blue printed and balanced
performance valve job some
Ptr Carbon fiber intake
Holley EFI Terminator X Fuel Injectors 522-428X EV6, 42#
58# fuel pressure at the rail
90mm gold blade new GM throttle body
PSI special cable to go from factory 8 pin TB to a 6 pin TB.

The wiring harness and computer purchased from PSI - delivered with a factory 5.3 base tune. the 55' pickup had a stock 5.3 motor and put in the new one a week ago.

Two items I changed - idle values and injector flow #s (used 58/43.5 SQ root times 42#)
started truck today and broke the motor in -
not running rich. ran well for the most part.

Issue I have -
1. once the engine is at or above 195 degrees , if I step on the gas pedal to raise up to couple thousand RPM, if I quickly lift my foot off the gas pedal the RPM will drop way below the 875 value in the table and engine will quit and/or severely stumble
If I hold my foot on the pedal and slowly lower rpms till they are near 875 and let the engine settle in, it will not quit and holds the idle nicely.

I figure this WAY beyond where I am right now and if I start screwing around to much will make things worse I figure - LOL

Just looking for a push in the right general direction -

I just need it to run decent enough I can drive it (for tuning) and get it to an alignment shop.

Thanks in advance
Bill

[04silverado6.0]

Do yourself a favor and buy a injector set with gm hpt data.

[ns158sl]

Do yourself a favor and buy a injector set with gm hpt data.

This.

But no one can help without a Tune let alone a log with the tune.

[BillCham]

I will be posting the HPT file and log in the am tomorrow.
Laptop is at the shop

Thanks. Bill

[BillCham]

Hey ...

I figured things out.
MAF and Idle Airflow were all sorts of screwed up. plus a handful of other small things.
Idles like a charm now -

I can take it to the alignment shop and get a tuner to work out all the fine tuning items ---
Thanks - Bill