Cold start issue
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CF Beginner
Joined: Jan 2019
Posts: 2
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Cold start issue
2008 Chevrolet Silverado 1500 5.3 liter vortec 4x4.
Rough idle (Signifigant bouncing rpm) for 15-45 seconds when cold started. Once warm it runs and idles perfect.
Not throwing any codes.
Was just at the mechanic for new AFM and normal valve lifters.
It has new machined heads and *new* intake and exhaust gaskets. New spark plugs.
Problem started 3 days after the $4000 repair.
The thottle body has been cleaned, idle relearned, codes reset my shorting battery terminals, sensors checked and mechanic has tried swapping "multiple components" and doesn't know what to do.
Wants to send it to a dealership for computer reflash and go from there.
Mechanic did do a unlit propane test at intake gasket, but I'm not sure if it was during cold start or after it had warmed up. I have video of how it sounds if there is a way to send it to you. Didn’t work to attach.
Looking for anything to help us troubleshoot this. Huge thanks in advance.
Rough idle (Signifigant bouncing rpm) for 15-45 seconds when cold started. Once warm it runs and idles perfect.
Not throwing any codes.
Was just at the mechanic for new AFM and normal valve lifters.
It has new machined heads and *new* intake and exhaust gaskets. New spark plugs.
Problem started 3 days after the $4000 repair.
The thottle body has been cleaned, idle relearned, codes reset my shorting battery terminals, sensors checked and mechanic has tried swapping "multiple components" and doesn't know what to do.
Wants to send it to a dealership for computer reflash and go from there.
Mechanic did do a unlit propane test at intake gasket, but I'm not sure if it was during cold start or after it had warmed up. I have video of how it sounds if there is a way to send it to you. Didn’t work to attach.
Looking for anything to help us troubleshoot this. Huge thanks in advance.
CF Monarch
Joined: Oct 2017
Posts: 4,605
Likes: 269
From: USA
2008 Chevrolet Silverado 1500 5.3 liter vortec 4x4.
Rough idle (Signifigant bouncing rpm) for 15-45 seconds when cold started. Once warm it runs and idles perfect.
Not throwing any codes.
Was just at the mechanic for new AFM and normal valve lifters.
It has new machined heads and *new* intake and exhaust gaskets. New spark plugs.
Problem started 3 days after the $4000 repair.
The thottle body has been cleaned, idle relearned, codes reset my shorting battery terminals, sensors checked and mechanic has tried swapping "multiple components" and doesn't know what to do.
Wants to send it to a dealership for computer reflash and go from there.
Mechanic did do a unlit propane test at intake gasket, but I'm not sure if it was during cold start or after it had warmed up. I have video of how it sounds if there is a way to send it to you. Didn’t work to attach.
Looking for anything to help us troubleshoot this. Huge thanks in advance.
Rough idle (Signifigant bouncing rpm) for 15-45 seconds when cold started. Once warm it runs and idles perfect.
Not throwing any codes.
Was just at the mechanic for new AFM and normal valve lifters.
It has new machined heads and *new* intake and exhaust gaskets. New spark plugs.
Problem started 3 days after the $4000 repair.
The thottle body has been cleaned, idle relearned, codes reset my shorting battery terminals, sensors checked and mechanic has tried swapping "multiple components" and doesn't know what to do.
Wants to send it to a dealership for computer reflash and go from there.
Mechanic did do a unlit propane test at intake gasket, but I'm not sure if it was during cold start or after it had warmed up. I have video of how it sounds if there is a way to send it to you. Didn’t work to attach.
Looking for anything to help us troubleshoot this. Huge thanks in advance.