Strange boost cut like the feeling of hitting a pot hole.

[JimmyT]

Strange boost cut like the feeling of hitting a pot hole.

Car revs fine at full throttle if you go thru each gear in turn but if you are doing 30mph in 4th gear then feather the throttle and get up in the rev range moving to full throttle it'll kinda do a jolt or large "Hickup"

If you then immediately change into 3rd and fully rev the car then go into 4th itll be fine at full throttle and not jolt.

Has anyone heard of this before?

Cheers J

 

[evoman2372]

Have you got a boost gauge? That will show if you are going over the threshold

 

[JimmyT]

Have you got a boost gauge? That will show if you are going over the threshold

Yes I have a boost gauge. What do you mean by threshold? Like the wastegate opens due to over pressure?

 

[JimmyT]

I have been advised to change the fuel filter as it may have not been changed in ages

 

[Dvolution]

Had a similar issue recently. Felt like all 4 wheels hit a pothole when accelerating. Had a dead spot in my throttle position sensor. Was from driving my car like a grandpa during my monthly drives while the car was stored for a few years. Try opening the throttle blade all the way a few times with the engine off. That cleared up mine.

 

[Tedrogers]

Strange boost cut like the feeling of hitting a pot hole.

Car revs fine at full throttle if you go thru each gear in turn but if you are doing 30mph in 4th gear then feather the throttle and get up in the rev range moving to full throttle it'll kinda do a jolt or large "Hickup"

If you then immediately change into 3rd and fully rev the car then go into 4th itll be fine at full throttle and not jolt.

Has anyone heard of this before?

Cheers J

Thanks for raising this problem as my evo 8 is doing exactly the same.
It is a fairly recent purchase and been standing for sometime I gather.
It is booked to go into CPP Congleton Cheshire.
Thought mine was the only problem evo so relieved others have had this problem and the answer seems straight forward.

Big thanks
I

 

[JimmyT]

Changed fuel filter but problem continue's

 

[Matthewbrowne]

What's happening is that you boost is creeping over the safe limit set by the ecu
This then prompts the ecu to cut the fuel and the car feels like you hit the brakes
Check your boost and find out what your ecu is set to usually between 0.9.and 1 bar as standard fuel cut usually hits between 1.1 and 1.3

 

[evo5kier]

Have you tried gapping the spark plugs to the correct gaps 0.5 I believe is the norm

 

[k2ggy]

I had to replace my mr 340 with spark plugs which cured the problem straight away.. if correct the plugs was same as a Toyota vitz which is similar to the evo