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Old 10-30-2018, 11:41 AM   #46
SRT8-X
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Join Date: Feb 2017
Location: Cypress, Texas
Posts: 42
Re: '69 C10 327 SBC Off Idle Stumble / Misfire Help - I feel like I've tried EVERYTHI

Quote:
Originally Posted by Fbks_Cruiser View Post
Quote: “I lowered the idle to 650 RPM or so, set initial to 12° (it was confirmed only the 4° off from my initial 16° setting so timing was accurate anyway) and 36° at 3000-3200 RPM.

I ran the engine at various RPM in the garage while working on this and getting to operating temps. This was likely 25-30 minutes as I was doing a few other things, looking at vacuum (dropped about 8-10" due to idle speed)” Quote

Your initial post said you had about 20” of vacuum at idle. Does this mean you now only have 10” vacuum at idle? That is way low. Barring a vacuum leak somewhere, such low vacuum indicates possible valve issues as discussed in other posts
Sorry for the mistake, I meant to write 8-10%. The vacuum at the low idle was around 18-18.5" Hg. It still had a minor drop / fluctuation at idle at times and was steady at times as well during this tuning.
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1969 C10 Stepside (PERCY - tribute to CDE)
1996 Chevrolet Tahoe 2-door / 2WD LS5.3/4A (ROBYN)
1998 GMC SLE Regular Cab Short Bed Fleetside 4.3/4A (LUCY) (driver)
2000 JEEP Cherokee Sport XJ 4x4 4.0/4A (RUBY, son #2)
2013 VW GTI Driver's Edition 1.8T/6A (GRAU GEIST, son #1)
2016 BMW X5 xDrive50i MSport 4.4L N63/8A (SCHNEEWITTCHEN)
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