Rough idle on warm start up

[19GTDude]

Hi guys. Picked up a 2019 GT 6 speed last Friday. 12K on the odometer and has been well taken care of. I've noticed when I restart the car while warm it tends to be a little rough and it did die once. After about 10 seconds it clears up and idles fine. It acts as if is flooded. No other issues idle wise. Issue does not occur on cold start up. You can shut it off warm and restart in as little as a couple of minutes and it will happen. I can clear it out by giving it some throttle. Stock air box and no other mods done. Any ideas? Thanks.

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[19GTDude]

Ended up with a CEL today. Code P0300 Misfire. Decided to replace the air filter (which was dirty) and clean the mass airflow sensor. No more rough idle during a warm start. Cleared the code and it didn't come back yet. Perhaps that did the trick???

 

[Dominant1]

P-0300 is a random misfire, check your plugs if the code comes back. If they are toast replace them. Get some Lucas injector cleaner, it works really well on dirty injectors.

 

[19GTDude]

My man.

 

[Dominant1]

That was quick... lol

 

[19GTDude]

That was quick... lol

We think alike. I had picked up four bottles. Been filling up with BP 93 octane and put my first bottle in a few hours ago. I honestly think the MAF was dirty from the dirty air filter. That's what I am going with until it starts acting again.

 

[Elp_jc]

I bet the previous owner put a racing (oiled) filter, no? Stupidest thing you can do to a street car IMO. I assume you cleaned the intake tube too, right? Even on my new car, it was dirty ( but not oily), which was surprising. It has always been clean on all my previous cars. My filter is open, but dry (Bullitt), so the intake tube was dirty from the factory. Will check it again when I replace the filter maybe at 15K (it's already quite dirty at 4K), and it should be clean.

 

[19GTDude]

The car belonged to a former major league pitcher who traded in for a Volkswagen sedan (cheaper payment). The air filter I would guess was the original one. I held it up to the sun and could not see any light coming through. Some of that dirt had to have gotten to the MAF. In addition to the start up issue the idle was a little ragged. Everything is good now. All she is going to see is 93 octane and the next 4 tanks will have lucas fuel injector cleaner.

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