Can anybody shed some good light on what exactly causes the hesitation experienced by some under load at mid-rpm at wide throttle angle? I'm talking on a bone stock engine.

Things I think about are:

knock sensor "over-reacting" under load and taking gobs of timing out of the curve?

Lean a/f mixture under load (which could lead to knock sensor doing its thing?)

wastegate flapping?

the TGV throttle bodies dumping open, maybe causing lean condition?

I really have no idea, but I was wondering if somebody had the real explanation and maybe a cure. I'm not talking about going to an aftermarket ECU or piggyback, and not some quick-fix in the driveway, like resetting the ECU by taking the ground cable off and then driving the car like a wild man. Is there a different throttle position sensor or something that can be swapped or something like that? The very first WRX I drove had no hint of this herky jerk....I punched it at 2500 and it stormed up to the redline like a raging bull. My car sometimes has the hesitation slightly. What is it?

 

Maybe Subaru conservative ECU programming... or possibly the 3 in-line cats. Seems that the hestitation issue pretty much disappears for most people when they 'reflash' the ECU or even get a catless downpipe. Did for me!

 

its the tuning.

 

Its possible that the ignition advance multiplier went down because of bad gas(causing knock), which could cause hesitation at certain rmp...if thats the case, the multiplier will eventually go up again if there is no knock...otherwise you can reset the ecu and do the vishnu ecu learning trick. for more info do a search

 

Here here, this is the worse thing about this car (well this and the stereo). Everyday I pull out of my drive way, get it up on the street and punch it at about 2500 rpm .................................. FINALLY boast grabs hold and off we go, but man it seems like eons. I would like to fix this problem as well as it is by far the most annoying problem with this car.

 

get a catless uppipe, ported turbo, and engine managment, your turbo should spool up a lot quicker.

 

I'm EcuTek reflashed and 100% catless and still have hesitation even after countless ECU resets. Funny you mentioned the grounding mod... this weekend I dragged myself to do this and to my surprise the hesitation is GONE! Let's see how long it stays that way

 

yo wassup sweet asian wrx girl. haha, nah, j/k