Hi there

I have been having problems with my 1994 wrx import, for some reason when I accelerate on corners or around round abouts it jurks/splutters/hesitates with my foot on full throttle, but once I let go of the throttle I get a backfire but once I'm back on the throttle it's normal and goes off well, it's been happening for over a year and so far I have had a full service which included oil oil filter air filter fuel filter NGK spark plugs, I have also replaced the fuel pump for a 255lph one, still nothing any suggestions ?

At first I thort it could be low fuel? But I tried it with full / 3/4 / half / and quarter tank and it's still the same

It's p*****+ me off now lol and want it sorted

Mods are
z4 piggybacked ecu
Full decat exhaust
Td05 turbo

 

Td05 is standard for your car iirc
Have you checked for error codes?

 

Also worth checking the fuel filler neck. I had a v4 which had a rusty filler neck(quiet common on old impreza) and eventually started letting water in. It used to splutter on cornering. Can you hear the fuel tank depressurising when you remove the fuel cap?

 

Yeah nothing comes up, the only time the check engine light came on was on the motorway it stayed on for a while and went of itself, and that came up as the maf sensor, but i had my mechanic look at that and it's fine

 

Yeah I can hear it when opening the cap