Timing changes at idle.

[WACHS1981]

Im having a hard time getting my truck to idle in gear. Ive tried the idle relearn and it idles great in P/N. In p/n, its about 12-1 afr. In drive at idle it goes to 16-1 and climbs up from there. Ive been trying to tune this thing for a while. Why does the timing change, when it idles perfect, its about 16 degrees advanced, when it starts going crazy, the idle jumps to like 28 degrees at idle. Why all this jumping around. Its a 99 Silverado with a 5.3 and 4l60e. I plan on a turbo build and have installed a new Tick performance camshaft, springs and pushrods. Everything else is stock at the moment. Ive got 52 pound bosche injectors that have not been installed just yet. Im trying to get to the point I can drive the truck another month or two, before the turbo. Any ideas? cam specs are ADV DUR: 285 INTAKE AND EXHAUST. .630 INTAKE VALVE LIFT AND .598 ON EXHAUST. LOB SEP: 115 DEGREES

[G-Body]

What do your 4 main timing tables look like? any big jumps in spark advance between them? If there are large differences in advance between the high/low octane tables and the base spark vs airmass vs rpm in drive / park tables it could cause the idle to surge and advance to jump around as you come to idle.

[WS6FirebirdTA00]

Post your tune and a log.

[WACHS1981]

Ill try to post, but what info is needed. The entire tune that I have at the moment? Sorry, for the questions. How do I look at a tune in the repository without using credits? Ill get the hang of it soon, but it may take a minute.

[gagliano7]

Post your whole tune. Log into the hptuners website click on tune repository look up the tune you want to look at. Click on download tune file and when the prompt from hptuners comes up click on no thanks and you can look at tune. YOu can also compare your tune to the one you are looking at. The only way you will get help here is to post your tune.