Hi guys, got a problem with my Evo 7 GSR :

Sometimes my car pulls really hard and boosting properly to 25psi but sometimes it feels like there is no power at all.

-Same gas, same rpm and same road : I can climb up the hill in 5th gear without any problem. But sometimes I even need to change to 3rd gear to climb the hill (no power in 4th and 5th any more).

-Same gas, same rpm : sometimes boost to 25 psi, sometimes over boosting to 30psi and sometimes barely boost to 17psi.

-When car is running properly, i can do 350km per full tank. If it is running poorly(no power), I can do maximum 250km per tank ( I always fill up at the same gas station).

-Same ride, somtimes when I stop at the traffic light (car is running poorly) , I accelerate and the power is back and drive like a monster.

-I noticed that most of the time when the fuel level is low, car will perform poorly. If I stop at the fuel station and top up the fuel, the power will come back and feel like a totally different car.

-The power loss is huge. I can tell like day and night different. I just cannot find out any reason or any particular time/situtation why car will perform differently.

-Car performs different on the Dyno too. Sometimes I can make 220kw, sometimes can only make 195kw.

Mods I have :
-K&N Pod filter with rubber intake pipe (it was there since I bought the car)
-Walbro 255Lph
-Tomei full TBE
-Tomei Poncam 270 Type R
-Stock Turbo
-Grimmspeed 3-port
-SpoolinUP COP
-HDi intercooler + piping kit
-Turbosmart BOV
-Turbosmart Boost Gauge

This problem has happened since my car was stock with only the K&N pod filter.

What I have tested
-Try a manual boost controller -> No more overboost but still sometimes 25psi, sometimes 17,18psi.
-Boost leak test -> no leak at all
-This is not related to weather issue. Car performs differently in the same cold/hot weather. It can drive great in 10 mins and poorly after that.
-New O2 sensor -> not fixing the mph issue
-Got my car on the Dyno a few times but never find out any reason why. Car performs different on the Dyno too.
-Try searching on Evom and there are a few members were having the same issue but they never found out why.

It looks like there is a electrical issue with my car. I used to see arc jumping in the exhaust manifold. Also, when car is in perfect working order, I can use the remote control to lock the car. If car perform poorly, I can only use the remote control to unlock the car but cannot lock the car. For now, the lock button seems to be dead. 9 out of 10 I cannot lock the car (I am still be able to unlock it).

Now I am at total loss. Please someone give me some lights in this issue.

Thank you everyone for your input !

 

Sounds like it could be an issue with the MAF, have you checked that yet?

 

Dang it's like the Mother of All Electrical Gremlins! :}

 

Sounds like a possible ignition system issue, perhaps the spark is jumping to a different ground.

 

Tuner checked the MAF and they said it's all good.

I have been driving with the metal intake pipe for 2 years without any problem. Lately, my car keeps stalling when clutch-in. I took out the metal pipe and put back the rubber intake pipe and it fixed the problem.

So yeah, I am thinking MAF could be the issue but not sure how to check it properly ?

 

Anyone got any ideas please ?