This car has had this 2018 Mazda 6 since the begining, I bought it new in July 2018. The car runs great all of the time, it is just when you slow down for traffic and then accelerate, it hesitates. Like it has a bad accelerator pump or the timing is off(you know what I mean). But, since it isn't carburated, rebuilding the carburator is not an option. A couple year ago I took it into the dealer and they did a firmware upgrade and that didn't fix anything. So, I am thinking that either I take it back to the dealer and have them flash it again (I'm sure there are several firmware upgrades since then), should I buy and install a custom tune or just put up with it. The first two will be expenive, my patients are well, kinda, free. And about that "adaptive cruise control", it has to be monitored or it will slam on the brakes when you don't want because of someone moving over to turn or going down a hill. I like to let off the throttle going down a hill to save gas, not burn up the brakes.
Well you'd have to figure out exactly what's going wrong which can be very hard to do. But a mechanic like myself could take it on a road test when it has the flat spot. Our fancy scan tool would analyze the data and record. Then we can look at that information. Try to figure out what it is. But you could try some really good fuel injection cleaner. Dirty fuel injectors into that. As well. O'clocked fuel filter or a weak fuel pump. You can pressure test
Did this since new and after the dealer updated the ECM two years ago.