2011 2.7l occasional backfire on startup??

My 2016 4 cylinder manual does this sometimes, usually on the 1st start after not running for a few hours. Sometimes its a small one right at startup and sometime when I first press in the gas (less often). Always a fairly quiet, quick backfire.

Is the consensus that this is not something to seek maintenance over then, so long as it only happens around startups?

 

My 2012 has done it sporadically since new. Happens once a month or less on a cold startup.

 

Thread revival lol.

I have over 185k on my 2TR-FE and I have never experienced any backfire running or during crank-up even during Temps below 0. Sounds like a timing fault or a heavily fueled engine. I do run 89 octane year round and 93 a few times a year. I'd start by inspecting your spark plug gap and possibly cleaning a few sensors and see where that leads to. Even as simple as a fuel change may help.

 

My 2016 just did it this morning thought it may be due to the slightly cooler temps we've had lately. Started up then a pop followed by a flashing Maintenance light that went away about 30 seconds later. Ran fine afterwards, anybody else get a light when it happens? Or has anyone checked with a dealer on this? First time this has happened has 4500 miles.

 

Ignition timing is probably off. The flashing check engine light from what I remember is the knock sensor telling the ECM there has been a misfire. There is a limit to them in every vehicle except in Toyota vehicles. GM usually allows 12 then turns on the CEL.
My Tacoma has some horrendous spark knock and all my plugs are white as snow with aluminum specks on the porcelain. Overheated pistons because of Toyota's poor choice of ECM tuning.

If I were you go to the dealership and have them pull the freeze frame data and make sure the ECM has the most current software. Do not let them tell you it's normal because it's far from it.

 

My 2016 manual 2.7 just did it. I wish it backfired more often...it sounds like im driving a sports car

 

My 16 does not do that BUT when my engine is cold and I am accelerating I get a slight hiccup in the engine, almost like the timing is off. Feels like a rubber-band for a bit but once the engine warms up it stops doing that.

 

VROOM-phhttt
That's what it sounds like.
I remembered this post because the explanation that it may be leftover fuel burning off makes good sense so I tried the suggestion of letting it idle for a moment before shutting it off. Unfortunately I can't say for sure that it works 100% of the time. Next I'm going to try the opposite and shut it off immediately and see if that helps.

 

My 2008 does it. Did it when I got it around 130k, have 160k now. Sometimes if I rev it right after starting I can replicate it but it but only during the first few seconds of running.

I don't worry and consider it a non issue.

 

Initial start up is a very lean mixture of close to 18:1. The lean mix is very hot burning to warm the catalytic converters to 500-600 degrees. Seems my truck will get them very hot too. I have seen temperatures of 1800 degrees with about 75% load at WOT. That is near the melting point of the catalytic converter. 2000 degrees is the start of the melting point of the catalytic converter substrate.
Still no backfire even after startup on my truck.

 

Lean combustion is hot combustion. The air injection adds extra oxygen to increase temperatures of the exhaust stream at the same time my AFR goes to 18:1 granted this is measured in the exhaust stream but I have not seen a rise in injector duty cycle other than what is required for 2000-2200 RPM.