Car jumps at higher RPM

[Steelnation36]

Ok i just started feeling this happen. I just installed a new tranny. It shifts perfectly and have no shifting or clutch problems but i was speeding up in 3rd gear and at about 3500rpm the car started bucking. with the gas pressed in all the way or partially i tried it all and it just jumps around but the rpms slide up to maybe 3900 but thats it. Same thing happens in 4th gear around 3900rpm. I have absolutly no idea what the problem could be.

Any thoughts? Thanks

 

[No_Skillz]

Fuel cut? BLT done?

 

[Steelnation36]

boost leak test to be done tom. I wasnt sure if that was a possibility but i just realized the problem and its dark. Fuel cut i dunno. How would i know. I have 680 injectors and 255walbro pump running a 14b. Im not real familiar with the fuel cut.

I was just kinda worried it may have something to do with the tranny

 

[yesItsdsm]

Is your car tuned? That fuel system is overkill for a 14b.

 

[Steelnation36]

yea i know i was getting a evo 16g from a friend then my tranny went so i didnt have the money to get it the fuel system shouldnt cause problems tho would it?? i mean because of the 14b. it just will never be short of fuel i could always throw the old system on. the car was tuned not long ago. until it hits this rpm it runs perfect

 

[Steelnation36]

but could it be anything else?

 

[gstbuford]

you need to get a tune then it will stop
and 680s are pretty big for a 14g
they com stock with 450 injectors

 

[No_Skillz]

Fuel cut isn't caused by having too small injectors or pump or a tune. It happens when your MAF sees a certain amount of air, doesn't beleive that a stock system can handle it, and the ECU cuts fuel to save the motor. This is why I asked about BLT and fuel cut in the same breath. Once you have fixed all your boost leaks, your fuel cut should disappear if you're only running ~15psi on a 14b (that's nowhere near the max-out point of a 2g MAF).

And get an adjustable FPR for that fuel pump.

 

[Steelnation36]

aight thanks for the explanation i just made my blt