persistent issues with 2010 LLT V6 - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

Insan37 · 04-28-2026, 08:04 PM

I know this is a long post, but I wanted to provide every possible bit of information regarding this issue. Any help is very much appreciated.

2010 CHEVROLET CAMARO LT
3.6L LLT V6
AISIN AY6 6 SPEED MANUAL TRANSMISSION
HURST SHORT THROW SHIFTER
K&N INTAKE

WHEN IT STARTED GETTING COLD TOWARD THE END OF 2025, THE ENGINE STRUGGLED TO START AND THEN WOULD RUN LIKE IT HAD A BAD MISFIRE. ONCE THE ENGINE WARMED UP A LITTLE BIT THAT WENT AWAY AND THE ENGINE WOULD RUN FINE. THIS ISSUE GOT PROGRESSIVELY WORSE THE MORE I DROVE THE CAR. IN LATE DECEMBER/EARLY JANUARY, IT WOULD TAKE UP TO AN HOUR TO GET THE ENGINE RUNNING. ONE DAY IT SHUT OFF AND HAS NOT BEEN DRIVEN SINCE. THE ENGINE WILL START AND THEN IMMEDIATELY DIE. SOMETIMES IT WILL IDLE BUT WILL DIE IF THE THROTTLE IS APPLIED.

TRANSMISSION, NEW PARTS:
SLAVE CYLINDER, THROW OUT BEARING, CLUTCH, AND SOLID FLYWHEEL.
FRESH 75W-90 GEAR OIL.
REAR TRANSMISSION MOUNT

ENGINE, NEW PARTS:
AC DELCO AGM BATTERY
STARTER
HIGH PRESSURE FUEL PUMP AND GASKET
6 FUEL INJECTORS
THERMOSTAT HOUSING GASKETS AND O-RINGS
VALVE COVER GASKETS AND SPARK PLUG TUBE SEALS
INTAKE MANIFOLD GASKETS
EXHAUST MANIFOLD GASKETS
TIMING COVER GASKET
TIMING COVER INNER SEAL
VVT SEALS
FRONT CRANK SEAL
WATER PUMP AND GASKET
HARMONIC BALANCER
6 IGNITION COILS
6 SPARK PLUGS
THROTTLE BODY
THROTTLE BODY GASKET
4 CAMSHAFT POSITION SENSORS
4 VVT SOLENOIDS
CRANKSHAFT POSITION SENSOR
KNOCK SENSORS
PURGE SOLENOID
BOTH ENGINE MOUNTS
MASS AIR FLOW SENSOR

CHECKED:
ALL GROUNDS -- REMOVED GROUNDS AND CLEANED MATING SURFACES
COMPRESSION -- ALL CYLINDERS BETWEEN 175-180 PSI
TIMING COMPONENTS -- ALL TIGHT, ROUTED PROPERLY, NO PLAY IN CHAINS, GUIDES, OR TENSIONERS, NO BROKEN GEARS/TEETH, TIMING APPEARS TO BE CORRECT.
MAIN ENGINE HARNESS -- FOUND NO BROKEN OR RUBBED THROUGH WIRES, ROUTED PROPERLY, CONNECTORS IN GOOD CONDITION, HARNESS IS RELAXED/NOT STRESSED/NOT STRETCHED.
FUEL -- 70-85 PSI ON THE LOW SIDE GOING INTO THE HPFP, 1300 PSI AT THE RAILS/FUEL INJECTORS AFTER THE HPFP
INTAKE VALVES -- WALNUT BLASTED TO REMOVE CARBON/COKING
CAMSHAFTS/COMPONENTS -- LIFTERS AND ROCKERS HAVE NO PLAY, CAMSHAFTS ARE SOLID/NO CRACKING OR BREAKAGE
ROTATED ENGINE SO THE FLATTEST PART OF THE CAM LOBE WAS PERPENDICULAR TO THE HPFP ROLLER, HPFP SPRING WAS NOT OVER STRESSED WHEN INSTALLING, ROLLER WAS PRELUBRICATED BEFORE INSTALLATION.

Joe.G · 04-28-2026, 08:34 PM

If I were you I would look into the 02 Sensor, My Hemi acted the same way and all I would get is a Mis Fire code, The readings from the 02 even appeared to be okay, once swapped all was good again. I mean it appears you have replaced almost everything, It took me a bit to track it down myself.

KillboyPowerhead · 04-29-2026, 05:40 AM

I had an issue with a car that was hard to start when cold and would die unless I kept my foot on the throttle, until it was warmed up and then everything was fine. Ended up capping the EGR port at the intake manifold and the issue went away; suspect an issue with a stuck-open EGR valve and/or exhaust leak. This engine uses VVT to create an EGR effect; not sure if you can verify all four cam positions with a scanner of some sort. May be a long shot...

Insan37 · 04-29-2026, 06:49 PM

Quote:

Originally Posted by Joe.G

If I were you I would look into the 02 Sensor, My Hemi acted the same way and all I would get is a Mis Fire code, The readings from the 02 even appeared to be okay, once swapped all was good again. I mean it appears you have replaced almost everything, It took me a bit to track it down myself.

I hadn't considered the O2 sensors. I haven't received codes for them, other than cat codes every once in a while. While the exhaust was out when I removed the engine, I inspected the cats and they didn't appear to be clogged. Light passed through them without an issue. I will investigate the O2s though. thanks.

Insan37 · 04-29-2026, 06:51 PM

Quote:

Originally Posted by KillboyPowerhead

I had an issue with a car that was hard to start when cold and would die unless I kept my foot on the throttle, until it was warmed up and then everything was fine. Ended up capping the EGR port at the intake manifold and the issue went away; suspect an issue with a stuck-open EGR valve and/or exhaust leak. This engine uses VVT to create an EGR effect; not sure if you can verify all four cam positions with a scanner of some sort. May be a long shot...

I'd considered this as well. My brother had a 4th gen camaro that ran like this and it had an EGR valve. we changed the EGR valve and the spark plugs and the issue went away. hopefully with new VVT solenoids this wouldn't be an issue. I just don't know if I can read anything off the VVT solenoids with it running like this, or its lack thereof. My most recent code was for a cold idle issue that points to the Crankshaft position sensor. I plan on changing that again with a GM sensor.

Joe.G · 04-29-2026, 08:13 PM

A Bad cat probably isn't causing your issues, Just looking though them will not tell you if they are bad. I was not getting any codes for o2 Sensors either but they ended up being the problem. Just throwing it out there as I really didn't think it was my problem but it was. It seems lik you have threw a lot of parts at it already.

04-28-2026, 08:04 PM	#1
Insan37 Drives: 2010 Chevrolet Camaro 1LT RS Join Date: Apr 2025 Location: Fort Wayne Indiana Posts: 3	persistent issues with 2010 LLT V6 I know this is a long post, but I wanted to provide every possible bit of information regarding this issue. Any help is very much appreciated. 2010 CHEVROLET CAMARO LT 3.6L LLT V6 AISIN AY6 6 SPEED MANUAL TRANSMISSION HURST SHORT THROW SHIFTER K&N INTAKE WHEN IT STARTED GETTING COLD TOWARD THE END OF 2025, THE ENGINE STRUGGLED TO START AND THEN WOULD RUN LIKE IT HAD A BAD MISFIRE. ONCE THE ENGINE WARMED UP A LITTLE BIT THAT WENT AWAY AND THE ENGINE WOULD RUN FINE. THIS ISSUE GOT PROGRESSIVELY WORSE THE MORE I DROVE THE CAR. IN LATE DECEMBER/EARLY JANUARY, IT WOULD TAKE UP TO AN HOUR TO GET THE ENGINE RUNNING. ONE DAY IT SHUT OFF AND HAS NOT BEEN DRIVEN SINCE. THE ENGINE WILL START AND THEN IMMEDIATELY DIE. SOMETIMES IT WILL IDLE BUT WILL DIE IF THE THROTTLE IS APPLIED. TRANSMISSION, NEW PARTS: SLAVE CYLINDER, THROW OUT BEARING, CLUTCH, AND SOLID FLYWHEEL. FRESH 75W-90 GEAR OIL. REAR TRANSMISSION MOUNT ENGINE, NEW PARTS: AC DELCO AGM BATTERY STARTER HIGH PRESSURE FUEL PUMP AND GASKET 6 FUEL INJECTORS THERMOSTAT HOUSING GASKETS AND O-RINGS VALVE COVER GASKETS AND SPARK PLUG TUBE SEALS INTAKE MANIFOLD GASKETS EXHAUST MANIFOLD GASKETS TIMING COVER GASKET TIMING COVER INNER SEAL VVT SEALS FRONT CRANK SEAL WATER PUMP AND GASKET HARMONIC BALANCER 6 IGNITION COILS 6 SPARK PLUGS THROTTLE BODY THROTTLE BODY GASKET 4 CAMSHAFT POSITION SENSORS 4 VVT SOLENOIDS CRANKSHAFT POSITION SENSOR KNOCK SENSORS PURGE SOLENOID BOTH ENGINE MOUNTS MASS AIR FLOW SENSOR CHECKED: ALL GROUNDS -- REMOVED GROUNDS AND CLEANED MATING SURFACES COMPRESSION -- ALL CYLINDERS BETWEEN 175-180 PSI TIMING COMPONENTS -- ALL TIGHT, ROUTED PROPERLY, NO PLAY IN CHAINS, GUIDES, OR TENSIONERS, NO BROKEN GEARS/TEETH, TIMING APPEARS TO BE CORRECT. MAIN ENGINE HARNESS -- FOUND NO BROKEN OR RUBBED THROUGH WIRES, ROUTED PROPERLY, CONNECTORS IN GOOD CONDITION, HARNESS IS RELAXED/NOT STRESSED/NOT STRETCHED. FUEL -- 70-85 PSI ON THE LOW SIDE GOING INTO THE HPFP, 1300 PSI AT THE RAILS/FUEL INJECTORS AFTER THE HPFP INTAKE VALVES -- WALNUT BLASTED TO REMOVE CARBON/COKING CAMSHAFTS/COMPONENTS -- LIFTERS AND ROCKERS HAVE NO PLAY, CAMSHAFTS ARE SOLID/NO CRACKING OR BREAKAGE ROTATED ENGINE SO THE FLATTEST PART OF THE CAM LOBE WAS PERPENDICULAR TO THE HPFP ROLLER, HPFP SPRING WAS NOT OVER STRESSED WHEN INSTALLING, ROLLER WAS PRELUBRICATED BEFORE INSTALLATION.

04-28-2026, 08:34 PM	#2
Joe.G Drives: 2014 2SS/RS 6SP Ashen Grey Join Date: Aug 2021 Location: NY Posts: 1,879	If I were you I would look into the 02 Sensor, My Hemi acted the same way and all I would get is a Mis Fire code, The readings from the 02 even appeared to be okay, once swapped all was good again. I mean it appears you have replaced almost everything, It took me a bit to track it down myself. __________________ GM 3.91/TrueTrac OEM ZL1 Rims, 6 Piston Brakes & Side Skirts.ACST4 Splitter/Deflectors NPP M2W,GM Short Throw,GPI Ported Rod Mod,BO White PTB,CAI/JRE Scoop, GC Aluminum DS,Stainless Works Ceramic LTH/HiFlo Cats, Hotckis 1" Springs & Chassis Max Brace BMR Adjustable Swaybars,Trailing Arms, Adjustable Toe Rod, LCA & Z28 UCA Bushings Hendrix Solid Cradle Bushings Pedders Radius Rod Inserts Strut tower brace, Moroso Catch Can,SCT X4 Dynosteve,Remote Clutch reservoir,Hero Smoked Tail and 3rd Brake Light, Diode Dynamic SL1 Fog Lights AeroForce Dual gauge/Autometer pillar mount.

04-29-2026, 05:40 AM	#3
KillboyPowerhead Drives: 2015 Z/22 Join Date: Aug 2015 Location: Ontario, Canada Posts: 994	I had an issue with a car that was hard to start when cold and would die unless I kept my foot on the throttle, until it was warmed up and then everything was fine. Ended up capping the EGR port at the intake manifold and the issue went away; suspect an issue with a stuck-open EGR valve and/or exhaust leak. This engine uses VVT to create an EGR effect; not sure if you can verify all four cam positions with a scanner of some sort. May be a long shot... __________________ Overkill/Self Tuned; Mace Camshafts; K&N Typhoon Cold Air Intake; Ported 80mm Throttle Body/Intake Manifolds/Manifold Spacer; Solo Performance High-Flow Cats, Cat-back Exhaust; Vitesse Motorsports Throttle Controller; Elite Engineering E2 Catch Can; BC Racing BR Coilovers; JPSS Delrin Radius Rod Bushing Inserts, Sway Bars; Pegasus Aluminum Rear Cradle Bushings, Camber/Caster Plates; Z/28 Toe Links, Trailing Arms, Upper Control Arm Bushings, Rear Shock Mounts

04-29-2026, 08:13 PM	#6
Joe.G Drives: 2014 2SS/RS 6SP Ashen Grey Join Date: Aug 2021 Location: NY Posts: 1,879	A Bad cat probably isn't causing your issues, Just looking though them will not tell you if they are bad. I was not getting any codes for o2 Sensors either but they ended up being the problem. Just throwing it out there as I really didn't think it was my problem but it was. It seems lik you have threw a lot of parts at it already. __________________ GM 3.91/TrueTrac OEM ZL1 Rims, 6 Piston Brakes & Side Skirts.ACST4 Splitter/Deflectors NPP M2W,GM Short Throw,GPI Ported Rod Mod,BO White PTB,CAI/JRE Scoop, GC Aluminum DS,Stainless Works Ceramic LTH/HiFlo Cats, Hotckis 1" Springs & Chassis Max Brace BMR Adjustable Swaybars,Trailing Arms, Adjustable Toe Rod, LCA & Z28 UCA Bushings Hendrix Solid Cradle Bushings Pedders Radius Rod Inserts Strut tower brace, Moroso Catch Can,SCT X4 Dynosteve,Remote Clutch reservoir,Hero Smoked Tail and 3rd Brake Light, Diode Dynamic SL1 Fog Lights AeroForce Dual gauge/Autometer pillar mount.