Cobra surges(hesitates) when hard shifting only. Help!

Mineral_01'

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Hey guys, tried searching but found no exact answer. Anyway, I've got an '01 cobra with eaton supercharger and it has a surging or hesitation when letting off the gas on a hard pull and getting back into it on the next gear. It runs great under normal driving or soft pulls.
I've read it could be my pprv or an IAC problem. My fuel system is a stock '01 tank with avaitor pump and 20A boost-a-pump which should be plenty of fuel for only 446 hp. right? The car was professionally tuned with more than a safe air/fuel ratio and 16 deg. of timing.
I remember my tuner said he had to adjust the throttle plate screw (Accufab) to get the idle dialed in. It also has had a complete EGR delete as well. Could any of these mods have an effect on this?
Some other specs:
JLT CAI with 90mm MAF, 39lbs injectors
Longtubes
Off road H-pipe
10lbs. of boost
NGK TR6 gapped at .034
Those are the only mods I could think of that could relate to my problem.
Thanks for any help.
 

Jimmysidecarr

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Sounds like the classic modded Terminator "shift hesitation" or "wot shift hez", there are lots of threads on this but not many will have the word "surge".

The problem is correctable with either a series of tune corrections by your tuner facilitated via data logging and data logging feed back to your tuner(preferred).

Or the PPRV delete.
 

Ironhand

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Im gonna bet its the PPRV.

Datalogging is a must and I would look at your FPDC. Im guessing it's above 90%.
 

Mineral_01'

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Im gonna bet its the PPRV.

Datalogging is a must and I would look at your FPDC. Im guessing it's above 90%.

Really? 90%. Is this not enough fuel pump or is it because the PPRV? My tunner supposedly tunes terminators and blown cobra's all the time. Shouldn't he have seen the high FPDC and recommeded more pump or does the PPRV restrict flow that much.
Come to think of it before the professional tune, it did not have the surging or bucking problem. However, the pre-dyno tune was seriously unsafe with way to much timing and lean conditions.
 

kezell

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I had the studder, tried the PPRV delete and it still did it. My tuner was able to get it out. Its all gone now.
 

Mineral_01'

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Well yes, I would consider a data log and tune re-calibration, but my tune shop is like over two hours away and I would rather just try a PPRV delete. Thanks again for everyone's reponse.
 

MoKo_03SVT

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make sure to come back and update your/this thread, with the results, once you have finished deleting the PPRV.

good luck, hopefully the delete will solve the problem.
 

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