Another hesitation/stutter question but different
 

So I have searched threads here and haven't seen this issue with OUT codes being thrown. My daughters 2012 1.8 Elantra stutters under regular driving conditions. You will be cruising say 40-60 mph and it will stutter like three or four hits then run smooth again. On a normal one hour drive this will happen like two or three times. I ran a bottle of fuel injector in the tank to no avail.
I checked for codes and there no odes being logged. I don't want to just throw money at it. Things I think it could be and tell me if I'm barking up the wrong tree please.
Dirty fuel injectors ( I plan on doing the manual cleaning of those this weekend ).
Clogged fuel filter or pump issue?
Mass Air sensor bad?
Head gasket issue? (Ive read there is a way to diagnose this via spraying carb cleaner around the gasket area while running?)

TIA for any suggestions
Brian

Maybe the trans slipping ?? Just a thought.

If you asked 3 or 4 different people to describe a misfire you could get 3 different descriptions.
So,,,,,,,,what would be helpful is, if you could describe in the best detail you can, like does it "stutter" like if you momentarily turned the key off , or maybe just seem to drag and come back up again. A momentary loss of ignition could produce something like a stutter, a fuel problem could produce a more extended loss of power , but to the average person they both could be described as a stutter, hope you can see where we are coming from,thanks.
Sorry I forgot mention as suelover questioned, so could a trans problem.

Ok I see where your coming from. If I am driving it the stutter I feels like a fraction of a second loss of power repeating about 2 or three times. Doesn't slow the car down. I can also feel it as a passenger. Hard to describe. Some others have suggested the camshaft positioning sensor may cause this.

Run a miss fire test
 

You can run a misfire. If you can't, remove the spark plugs and check for spark leaks. If the base of the plugs are red, replace them. If the gaps are burnt, replace the fuel pump and filter.

Now we have some idea of just what you mean.
Some folks call it a skip, some a miss, and some a misfire and they just about all can be caused by a brief interruption in ignition of the fuel mixture in the cyls.

When this happens the system monitoring engine performance will usually set a code in the pending section. we need to have the system checked for continuous AND pending codes.. What can you tell us as far as what kind of maintenance has been done to the vehicle.

From what you describe it could be a plug or coil breaking down under load. It will miss firing the plug or plugs, once in a while. That is felt inside the vehicle as an intermittent loss of power. Crank sensors don't always throw a code when thinking about going into retirement.
There is a function called MODE 6 that will tell us if this is occurring and which cyls are involved, but a capable scan tool is required to get this info.
It is either have some diagnostic work done or start replacing suspected parts, which can get expensive and disappointing and not recommended.

I ask about recent maintenance done because if for instance the plugs were replaced by a careless (person) one of them could have been cracked. When the spark doesn't get to the cyl as it should it finds a path to ground through the crack and does not have to happen all the time.

https://cimg9.ibsrv.net/gimg/www.hyu...f7bb500ba9.jpg
https://cimg8.ibsrv.net/gimg/www.hyu...59af5d7844.jpg
Spark plugs don't look that bad to me?

The OBD code checker I am using is a cheap ELM 327 blue one that you connect to a phone via bluetooth. Would this possibly be the resson I am not seeing any codes? It has worked fine on Chevy and Dodge's in the past.

The car has been fairly regularly maintained at the dealer and a local shop. Oil changes inspections etc.

I replaced the crank sensor to no avail.