turbo Silverado lean spikes/stumble

[BLK02WS6]

Working on a friends turbo Silverado with an E38 PCM. I don't have a ton of experience with them, mostly LS1 PCMs... I am thinking that it has a mechanical issue causing the stumble/miss and unburnt fuel is showing up as spikes on the wideband. It is plenty rich right before it happens and the spikes are sporadic and very large - not typical lean tune characteristics. Any help ruling out a tune issue would be appreciated! Tune and log attached.
Thanks!
Bret

[BLK02WS6]

Looks like the problem may have been the spark plugs - the guy he bought it from had the coldest LS race plugs you can buy in it... blowin the candles out! New plugs and we will give it another go.

[Mean Green Z28]

Woo!

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[joecar]

Bret, good job on diagnosing the plugs

[BLK02WS6]

Bret, good job on diagnosing the plugs

Thanks Joe! Hope to get a chance to catch up with you soon! Been far too long my friend!

[joecar]

Thanks Joe! Hope to get a chance to catch up with you soon! Been far too long my friend!

Yeah, too long... it'll be nice to chat on the phone

[BLK02WS6]

Unfortunately, it still has the issue... I'm going to try disabling the MAF and seeing if it does it. I saw a post on here where someone else had one that kept going lean with VE and MAF together, but wouldn't do it with each alone. His problem turned out to be some of VE calculation tables (forget which ones and I'm at work and can't look) and I tried those same changes, but it isn't helping this one...

[BLK02WS6]

I finally found a stock tune for this OS and started over - may have solved the issue. Still way too rich, but the lean spikes appear to be gone. Fingers crossed...

[Mean Green Z28]

Git 'er done!

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[BLK02WS6]

Git 'er done!

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LOL- waiting on you!