loss of power at half throttle?

[97gsxturbo97]

So I noticed that since I got the car there will be times when I am getting on the highway the the car will feel like its cutting power around 2500 rpm at half throttle. This happens as soon as I get into boost. The rpms will drop and I will feel like im being held back. In order to overcome this I have to let off or floor it. I dont know what this is?

I have done boost leaks tests, changed the plugs, cleaned the mas, and looked over everything.

I did find out one thing today. On RRE website it mentions that the MAS has an adjustment screw in the bottom. It says from the factory this screw is screwed all the way in and to lean out the car you can screw it out. Well I took out the blob of silicone and the screw was already as far out as it could be? Is this my problem? Why would the factory set it up like this if it is suppose to be all the way in?

 

[DeadsEvolution1]

How much boost are you running?? I see that you have a FPR but do you have an aftermarket fuel pump and injectors??

 

[Afroclipse]

sounds like you are rich

 

[97gsxturbo97]

car has stock fpr and stock fuel pump, stock ecu. I did some searching and it sounds like lean surge?

 

[DeadsEvolution1]

Sounds like fuel cut

 

[Demon33]

So I noticed that since I got the car there will be times when I am getting on the highway the the car will feel like its cutting power around 2500 rpm at half throttle. This happens as soon as I get into boost. The rpms will drop and I will feel like im being held back. In order to overcome this I have to let off or floor it. I dont know what this is?

I have done boost leaks tests, changed the plugs, cleaned the mas, and looked over everything.

I did find out one thing today. On RRE website it mentions that the MAS has an adjustment screw in the bottom. It says from the factory this screw is screwed all the way in and to lean out the car you can screw it out. Well I took out the blob of silicone and the screw was already as far out as it could be? Is this my problem? Why would the factory set it up like this if it is suppose to be all the way in?

I would check your TPS (Throttle Position Sensor) for proper operation/resistance across its entire range. It sounds like you could have a bad spot in its travel at about the 1/2 throttle position. If this is causing a faulty position reading to be sent to the ECU it could cause improper timing or fuel delivery. The fact that you said, "In order to overcome this I have to let off or floor it" makes me suspect the TPS is acting up at that throttle position. The check should be pretty quick and easy using a multimeter.

Good luck.

 

[97gsxturbo97]

well it doesnt do it all the time, it seems to only do it between 2500 and 3000 rpm? Wouldnt the tps cause this all the time and not at certain rpm? One other thing I was thinking of was the stock BCS was fluctuating boost and causing this? The boost goes up but the car seems to slow down. That is what is happening. If I hold it the car will eventually start to accelerate again.

 

[LiquidX]

Couple things, did you tune it and if so, what's the readings in that rpm range? Getting pulled timing? How about any CELs?

 

[hhuricane]

It could be a TPS. If you have a datalogger you can check to see if the TPS reads smoothly through its range. Sometimes they will get a dead spot in them and start to mis-read in certain places. Also check your hose, you could have a boost or vacuum leak.

 

[Kantide]

I have this problem as well but it does not always happen. I still somewhat believe that it is my clutch slipping, but that doesnt seem right as if it was slipping my RPMs would still increase but not speed, when this happens it feels like everything is bogged. I am going to change my spark plugs and see what happens.

 

[97gsxturbo97]

The car is not tuned, it is on the stock ecu. The car did this since I bought it. I assumed it was becuase the stock bov was leaking air making the car rich. The car now has hard pipes and 1G bov. Everything else is stock and the car is also an Automatic.