Getting power stutter through Rev range

Hi all

I have a stock 91 gto twin turbo, Ive done cat delete, new 3” exhaust straight a hose delete
And put a mbc in place wound down . Running 9/10 psi .
The car powers well up to 4/4500 revs then cuts ( split second then powers ) change gear and still does it ( sometimes cuts at a higher or lower Rev range ) before fitted no faults at all .
If I’m gentle on the throttle it will power through but gentle .i don’t want massive boost just as is 9/10 psi .
Thanks in advance

Any ideas


You need to retrace your steps and undo what you’ve done until you solve the problem.

I doubt it will have anything to do with the exhaust so long as you still have the lambda sensor.

Probably to do with your vac lines but tbh, I wouldn’t be messing with the boost at all if you’re not changing anything else n keeping stock boost I would put the original Solenoid back in and do away with the mbc. You may just just have missed a vac line off somewhere.


Hi jus

Thanks for your response
Even before I did hose delete I had tried a mbc on low boost and still hit cut . I thought it was fuel pump now I thought it could be injectors.
But it does cut but will Rev through the range b4 red line .
It’s strange because if I’m soft it will power o. With no cut .
WTH all hoses are new or blanked .

Have you tried data logging?

Sounds like its being starved of fuel, it will cut the power, the timing won’t retard anymore to allow for the air/fuel mix, I would say wind your mbc back down to 6psi and see what it is like. Or get a logger and see what your trims are like

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Last thing you want to do is end up detonating

Does it go though 1st gear fine, then all the others it does it, my clutch is slipping and at first it was simular to what you have said and now I can’t put my foot right down in any gear but if I climb up the revs slowly it’s fine

Guys is very important that you use a data logger and log fuel trims and timing etc over the years this been said a lot of times and stressed about.could be doing damage and not knowing it.
Get logging!!!


Could it be plug spark blow out?

Cheers guy
I’m gonna check previous work for anything I missed , it has had plugs , coil packs ,ptu, fuel relay , re-con ecu .