misfire but no engine light on

Started the car today and it sounded like someone made a whole in my muffler...... took it to get it checked at my friends shop, no issues, no engine light, no codes. no nothing... drove it for about 5 minutes and nothing, still no check engine light..... im buying coils and spark plugs tomorrow anyway, but does anyone knows what it may be the problem ???

Hi,

I Had a similar issue, I changed Fuel Filter, coils and plugs, and the issue always returned after a while, I even used Injector Cleaner for a while when I fill up,
mine was intermittent with no Codes, normally when the car was warmed up and I Drove in traffic it would misfire/backfire/after fire when I decelerate on the overrun or at idle.

I checked the Injectors, LPFP, HPFP, Changed DV to latest revision, all with no improvement.

I even ran logs and got it professionally diagnosed and tested, they checked Spark, timing, Fuel, vacuum, and boost leaks and everything else.

Alas I gave up, but then Carbon Build Up came to mind, so for the last week or so I would let the car warm up to operating Temp, and then on my highway commute (15 to 20 minutes) I will drive it in S Mode or M mode to keep the RPM’s at +/- 4000
This “Italian Tune Up” seemed to clear up some of the Carbon on my Intake Valves and the problem has stayed away thus far.

Try it…