However , fuel distribution or injection can be fine up-to 4000 rpm and then start to depressurize or something ?
Are you telling us or asking us?
I didn't got that direction for him since he mentioned it was missing under load
There was no mention of the issue occuring under load, whether that be the case or not.
Throttle body or maybe head gasket not torqued to spec ? guess I won't make sggt on the Pentastar any more .....srry , op
LOL... No, no and probably a good idea.
Thanks all for the replies. I want to make my self clear on my issue. The only time I feel or hear the studder is when I am accelerating above 4000 rpm and only when it shifts gears, no other times. The best way to describe the studder feel and sound is like a studder box on a dragster at the tree when he is revved up waiting on the light, hopefully some of you know what I mean.
The other issue is a loss of power and lazy shifting in the trans but neither of these are always present but they are present at the same time with each other when it occurs. The studder is there all the time whether I let the trans shift in auto or if i manually shift it.
I can go to the dealer on the studder but the lazy shifting and loss of power isn't always present for me to show them, maybe it is all tied together. The other reason I hate going to the dealer is well, it's the dealer and I don't always trust there answer and it is more throwing parts at it on multiple trips instead of fixing it the first time.
I am going to re-install my factory exhaust this weekend and if that doesn't solve the issue then I guess I will take it to the dealer.
Take it in. It's really going to be difficult to diagnose over the internet unless it throws a code or you can see a hard failure. It is probably under warranty if it can be traced to a failed part, anyway. You should not have to take the exhaust off under the magnusson moss warranty act unless you think you might have left a chunk of soemtihng in the exhaust tubes or have other reason to believe that it is severely restricted. If it can be traced to bad gas, plugged fuel filter or bad work by someone else then they will charge you. I think even a failed spark plug should be covered, for example, if it failed electrically or materially (read: not "wear") and before the service interval. I don't think you should even be on the hook for the diagnosis cost either unless it is proven not to be a failed factory part. IIRC, warranty operations either include diagnosis time or there is a seprate (and payable to the dealer) warranty operation code for the diagnosis.
If it is happening under free-rev then its most likely in the engine. It does sound like something is cutting out, like a spark plug, ignition coil or a subset of injectors.
It is a good suggestion that curing one might cure the other.