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Stalling Problem

il.Ari

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I have a 2016 5.0 with a whipple supercharger (whipple tune), borla long tube headers and a catback system. For a while now, when the car starts up, the needle bounces around at low revs and the car sounds like it's about to turn off, then the revs kick back up to normal after maybe 10 seconds or so. I've also noticed that the vaccum reading has dropped significantly and I idle around 14-17 inHg. When I step on the gas, even mildly, I notice a lot less response and power than before and the vaccum gets to below 10 inHg. On top of this, the car has started stalling now. Randomly while driving, the engine will just shut off and the built in gauge readings will tell me my oil pressure is low and the engine won't stay running if I try to start it again. I had it towed to a shop a couple times since it keeps stalling in the middle of me driving and by the time they go to check on the car, it starts up just fine. Any suggestions on what I could check myself or tell a shop to look at?
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SheepDog

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check these:
Fuel pressure
Compression and leakdown test
Vaccum leaks
MAF dirty or bad
Bad/damaged throttle body
Bad battery

Any codes? Do you drive it like you stole it?
 

Pistol_91

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Sounds like you answered the question yourself. Sounds like a vacuum leak. Have you changed anything from since it ran fine to now?
 

JetGray_Mach1

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I would do codes, checking Vacuum leak then MAF. Those are the most likely culprits.
 
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il.Ari

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check these:
Fuel pressure
Compression and leakdown test
Vaccum leaks
MAF dirty or bad
Bad/damaged throttle body
Bad battery

Any codes? Do you drive it like you stole it?
Thanks I'll give those a check, the car popped codes a while back but I don't remember the exact codes but I'll give an update once I check them again. I drive as tame as possible honestly, the codes randomly popped up one day after replacing my brake pads and rotors...
 

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il.Ari

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Sounds like you answered the question yourself. Sounds like a vacuum leak. Have you changed anything from since it ran fine to now?
The codes popped after I swapped out my brake pads and rotors but that clearly has nothing to do with it. Could be worth noting that the long tube headers have no cat converters and to prevent codes, the previous owner has extensions on the O2 sensors.
 

Pistol_91

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So then where are the rear o2s installed at? There should be extensions on the front o2s which is normal but the rears should of been disabled in the tune and the plugs ziptied up and out of the way ... The rears typically wouldn't cause the car to stall either, but who knows. The first thing I would check is for vacuum leaks. Try to feel around with the engine running and see if you find a spot sucking some air in. If not check the spark plugs next. Could have a bad one and that would cause issues for sure.
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