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Engine hesitation and surge

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Hi. I have a Subaru Forester 2000.year Turbo.

I built my engine stock mode. stock poistons rings valves vs...

after cranking when I am pressing the throttle pedal slowly engine is starts hesitating and surging.

like somebody is pulling the car when I pushed the gaz pedal.but when I am slowly unpressing the gaz pedal engine comes normal.

I bought and changed these .: crank sensor knock sensor,cam shaft position sensor,MAF sensör,spark plugs,new sparks NGK pfr6b iridium, ignition coil, TPS sensor, and adjust the tps sensor (recomended value 0,45 - 0,55) I use all the number 0,45-0,46-0,48-,50-0,55 ,

and also change new wastegate,air filter, reset the ecu,But nothing changes.

The engine makes like a launch control symptom and when I am depressing the gaz pedal ıt comes normal speedly.

I need your help..

I will make some tuning with using my watched lessons but I cant find my car problem.

Waiting your Good advices

Check for vacuum leaks. There are YouTube videos which show how to do this with carburetor cleaner.

I checked All vacum lines with carburetor cleaner a and lots of methods no leaks.

and also checked all exhaust leaks manifol leaks nothing found every thing is ok.

have you checked your mechanical timing is right and vac lines are routed correctly?

YEs I checked timing several times and everything is ok. and also vac lines are roted correctly.

Any advice ?


Are you using the stock ECU with your new engine?

And since you've had the engine out and back into the car, I'm wondering if you could have a wiring issue. I've pinched and cut wires before when removing and replacing an engine and that might have happened to you.

I did not see it above so,

have you tested fuel pressure while you have this issue?

Spark plug wires are routed correctly and are securely connected to both plugs and coils? (I had an issue where a wire had pushed itself between the plug and bore, but looked like it was set correctly.)

Is there a possibility you have connected a harness connector to a different plug?

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