C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

Po400 ????????????

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Old Aug 5, 2005 | 01:42 PM
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Default Po400 ????????????

I get a PO400 code (EGR malfunction) after a 40 mile freeway drive and come to a stop at the exit. Dealer can find NO problems anywhere except to say that to solve the problem I need to put the stock exhaust back on because the loss of back pressure is what is tripping the EGR code.

HELP PLEASE
Old Aug 5, 2005 | 01:47 PM
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with as many cars as there are around here with aftermarket exhausts, this would happen all the time
Old Aug 5, 2005 | 01:55 PM
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Okay...does anyone have better advice for me than what the dealer told me??
Old Aug 5, 2005 | 03:01 PM
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Tell the dealer. "Thanks for nothing. Can you recommend someone that knows what they are doing?". That'll get his attention.

RACE ON!!!
Old Aug 5, 2005 | 03:12 PM
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What year?
Old Aug 5, 2005 | 05:07 PM
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Originally Posted by cuisinartvette
What year?
1996 LT1 with automatic trans.
Old Nov 18, 2012 | 11:06 AM
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Same issue here. 1996 LT1 Vert. I have factory CATS, resonator removed, straight pipe going into Magnaflow Axlebacks. I can clear the code, after about 20 miles of driving code returns.
Old Nov 18, 2012 | 01:55 PM
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Originally Posted by 90_vette
Same issue here. 1996 LT1 Vert. I have factory CATS, resonator removed, straight pipe going into Magnaflow Axlebacks. I can clear the code, after about 20 miles of driving code returns.
http://forums.corvetteforum.com/foru...s-or-more.html

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