hesitation and running issues.
 

I am having hesitation issues.
Very random.
Worse when cold... but still there when warm.
I have replaced O2 sensors(ngk)
Spark plugs (ngk laser iridium)
Knock sensors
Coolant temp sensor (oem)
MAF (twice)
TPS (and tested to make sure it is fine and adjusted with meter)
Cam and crank sensors
Intake gaskets
Alternator (maniac)
All vacuum hoses under intake
Fuel filter AND 6 new fuel injectors.

Any one got any other ideas?
Anyone know of somewhere in central Florida I could take it and get reputable service?

Re: hesitation and running issues.
 

I would suspect one or more bad coil packs. I had similar issues and that was the culprit.

Re: hesitation and running issues.
 

Have a look at the intake right before it gets to the throttle bodies. The big plastic one. There are many nipples for large hoses to connect to. Maybe one of them is cracked and has a leak.

Another thing that comes to mind is the engine/chassis/battery grounds. Make sure they are all good and solid. You can add an engine>battery ground if you want to as well.

Re: hesitation and running issues.
 

Same with me.

Re: hesitation and running issues.
 

is there a way to test them to see if one is the culprit and which one?

Re: hesitation and running issues.
 

With the car running and hesitation present, disconnect one at a time. If the hesitation gets worse, that one is OK. If the hesitation stays the same you've found your man. If more than one is bad you could leave the bad one disconnected and continue to pull one at a time and see if there is any change.
After I changed my plugs and one bad coil I broke down and brought it in to a local Subaru specialist. He diagnosed and replaced another bad coil with a spare I supplied.

Re: hesitation and running issues.
 

too random for that.
also it is only when driving.
idle is so smooth

Re: hesitation and running issues.
 

I have some spare coil packs you could use to diagnose whether one is bad.

Re: hesitation and running issues.
 

I would try the coils as well. I had this issue, one of my coils was lazy. It would work occationally and not at full strength. Borrow the coils and try one at a time, drive with it for awhile and then switch to the next one until you find the bad one. Time consuming but worth the effort.

Re: hesitation and running issues.
 

At what rpm range do you experience this? I swear I've done everything you have and my vehicle does this mostly when the engine is at temperature.
The only things I haven't done were replace the complete throttle body and place in a new IRIS valve.

Re: hesitation and running issues.
 

Very random.
2200 to 2300 rpm is the most common.

Re: hesitation and running issues.
 

curious, did you resolve your issue?

Re: hesitation and running issues.
 

no
getting worse... hopefully will throw a code...
frustrated

Re: hesitation and running issues.
 

Do you have a stage1av1 chip?

Re: hesitation and running issues.
 

Not yet.
Hopeully next paycheck.