Sorry if this has been covered, I couldn't find the solution by searching.

Recently changed serpentine belt, car really seems to accelerate and shift better and smoother.
intermittent misfires in cylinder 4 and 6, strong gasoline smell from exhaust
when I pulled over. After scanning for error codes all I got was the 3 misfire codes.
After restarting the car, all is back to normal and I continue on my way.

This happend 2 days in a row on cool mornings.

65k miles currently

Can an old battery cause misfires?

Can a loose gas cap cause misfires?

 

Is this indication of injector failure in the near future?

 

Found a TSB on this, apparently if misfires are only on cold start and engine temp is below 76c (which mine is)
this is due to PCM calibration issues and needs a software update.

https://static.nhtsa.gov/odi/tsbs/20...18162-9999.pdf
(applies to 5.0 engines)

Also my car is running Quantum tune which could amplify the issue.\

I will warm my car up to >75c before driving off in the morning and report back.

 

Update: The issue has not come back, however I did put a bottle of royal purple injector cleaner
in the tank just incase. Bad gas is also a possibility.

 

I should have read this more carefully.

I thought 'cold start' was refering to an air temperature below 76 deg F but it is actually a coolant temperature below 76 deg C (167 deg F). Regardless of where it is in the World, that's not a cold start, it's a warm start. 76 deg C must be the coolant temperature parameter at which, from a genuine cold start, the engine revs drop from elevated to normal.

As the TSB makes clear, no recall to fix an identified software issue - only take action if a customer complains.

Graham

 

Correct, thanks for clarifying.

Being in Hawaii, Im probably on the cusp of
that threshold very often, being a daily driver.