Hesitation
 

From 1k revs to 3k the car seems to hesitate, once on boost all is fine, this seems to happen in all gears.
Any ideas?

Turbo Lag? lol

Cheers, what is the best fix if any?
It also seems to d this when pulling away in first and is very hesitant until 3k revs??

Bump. Any ideas on what the possible causes for this are so that I can eliminate them one by one.....

Is the car an STI?

Only reason I ask is that my Blob STi is a bit like this, and is down to the bigger VF35 turbo, where as the WRX has a smaller TD04/05 turbo.

The Scooby has never known to be quick off the line unless you want to rev past 3K and dump the clutch. (Note: doing this a lot will shorten the clutch life)

The turbo on a none Prodrive Performance Pack or remapped engine will come on around 3K RPM. On a PPP car this comes down to 2.5/2.8K RPM.

The fix? A remap of the car engine to allow the turbo to come on earlier or something called anti-lag. Or even a different Turbo and remap will help.

The other thing to consider is that the clutch on the Impreza has something called Clutch judder, so first thing in the morning when the car is cold you may find the car more hesitant becuase of the clutch as well.

On the APFC you could advance the timing to mybe +2 or +3 and fuel enrichment frm 1k rpm to 3k rpm

Or get a professional to do it. I recommend Simon Jolly Green Monster

you dont say what kind of hesitation it is, so go simple... is it a split or leak in the intake tract; between the maf and the turbo?

many reasons possible here.

Could also be lambda sensor. It goes well after 3k because ecu runs a closed loop then?:confused:

Had a similar thing. I'd try disconnect the lambda and see if it makes any difference. if it doesn't - it maybe a lambda then.

Checked All the above did find some clips loose and give the car a full service plugs/air filter/oil & filter/fuel filter.
Not had a chance to give it a good blast, the air filter was really dirty!

Forgot to add carried out ECU reset also

Will know after the weekend.

What year of car?

2002 52 plate

Mine - 51 plate - had a hesitation when accelerating, I had a K&N fitted... changed it for a Perrin short ram and that solved it, so it could have been a dirty filter, maf connections, plug/socket.

Big differance now anyway...

best of luck with it.. feckin frustrating!

Some help needed chaps:
Today when pulling away slowly (not on boost) and driving under 3k the car is hesitating, like miss firing but it is not, if that makes sense?
Once on boost all is fine, also noticed once on boost and say change gear at 5k then under acceration it hesitates for couple of seconds (still above 3k) then of she goes.
Any ideas.

Cheers.

what spark plugs are you using?

These ones:

NGK Spark Plugs Platinum PFR6B gapped at .7mm
Only fitted last week.

was it doing this before you fitted them?

Yep, seems to come and go?