sorry but im french
ill do my best

i'm on the road at aybe 80kmh

I accelerate , pedal to the floor, the rpm around 3500, reach 4800, then goes down to 3700 and accelerate HARD

why do I have a peak to back down at 3700 rpm after

i got a 04 A4 C5

 

Bon jour...votre English c'est good...someone will help soon.

 

Try this:

Manually shift the transmission thru the gears. If the RPMs increase smoothly in each gear, you may have a transmission issue.

If the engine stumbles at the same point in each gear, its could be an engine issue.

Are you seeing any check engine lights OR flashing Check Engine Lights OR messages in the DIC when the problem happens??

Reading your DTCs:


READING YOUR Engine Diagnostic Trouble Codes (DTC)

This procedure should be carried out any time you experience a problem with your C5. Most inexpensive store bought aftermarket code readers will ONLY read power train DTC’s. Reading the DTC’s with the C5 built in code reader will allow you to read ALL the modules in the vehicle.

The Diagnostic Display Mode is entered with the following procedure:
1) Turn on the ignition but don't start the engine.
2) Press the RESET button to turn off any warning messages. (i.e. door open, trunk open ect)
3) Press and hold the OPTIONS button
4) While holding OPTIONS, press FUEL button four times within a 10 -second period.

Initially, the on-board diagnostics go into an Automatic Mode which will cycle through each module and shows diagnostic codes in a pre-set sequence: PCM - TCS - RTD - BCM - IPC - RADIO - HVAC - LDCM - RDCM - SCM - RFA. All codes will be displayed for each module. ( i.e. PCM = 4 codes) If none are present in a given module, you will see No More Codes on the display.

There are two types of diagnostic codes, Current and History designated with a letter suffix, “C” or “H”. A current code indicates a malfunction is present in the module displaying data. A history code indicates a problem existed sometime in the last 40 or 50 ignition cycles. When not accompanied by a current code of the same number, it's potential evidence of a previous problem, now resolved, that was not removed by clearing the codes. More likely it's an indication of an intermittent malfunction.

Intermittent codes are the most challenging of the diagnostics. An intermittent code may have happened once, may have happened more than once but is inconsistent or may be happening on a regular basis but not at the time the codes are displayed. History codes can also be caused by a current malfunction in a system that is not operating at the time codes are displayed. An example is the rear window defogger which doesn't operate until the Body Control Module detects engine rpm. For history codes set by a module that does not operate with the key on and engine off, a special diagnostic tool called a Scan Tester is necessary to properly diagnose the malfunction.

Once the system has displayed all modules, it goes into the manual mode which allows selection of each module using combinations of Driver Information Center buttons. Manual mode can also be entered during the automatic sequence by pressing any button except E/M. Once the display shows Manual Diagnostics, select a module by pressing the OPTIONS button to go forward or the TRIP button to go back. Once a module is selected, a code is displayed, and if more than one are present; press GAGES to go forward or FUEL to go back.
To exit the diagnostic mode at any time, press E/M. If you want to erase codes in a given module, press RESET To reset the codes once in manual mode, press and hold RESET until it displays NO CODES Press OPTIONS to go to the next module. Repeat the steps until you have reset the codes in all the computer modules.
NOTE!! Only reset the codes IF you want to - it is NOT necessary to do this. Clearing a code does not repair a problem. You are simply erasing the evidence of it in the module's memory. If you clear the code/s, and extinguish the Check Engine Light, your emissions status ready will NOT allow you to pass an emissions test until you have completed the required driving cycles. There are a few body module DTC’s that if set will prevent the module from operating properly. Once the DTC is cleared, the module will return to full function. This is not true for power train DTCs.

If you have never read and cleared your codes, there will probably be a lot of old history DTCs. It is recommended that you clear your codes and see if any come back during a driving cycle. Those are the ones that you need to concentrate on diagnosing.

Once you have the codes, the next question is: What to do with the information?
First, consult the factory service manual. Any serious C5 Do-It-Yourself owner should invest in the Corvette Service Manual of the appropriate model year. The Service Manual is really a requirement if you want to understand and work on your C5.

NOTE and a WARNING. You can read the DTCs while the engine is running. I pull mine up all the time while driving.
WARNING. Don’t become distracted while reading DTCs while your driving and cause an accident!!!!! Use common sense and drive safe.

These are some very good C5 Diagnostic Trouble Code (DTC) explanation web sites!!! They also explain how to read the DTCs

Here are some very good sites that explain what DTC mean:

http://www.gearchatter.com/viewtopic11755.php

http://www.obd-codes.com/trouble_cod...d-ii-codes.php

Make sure to include the H or C suffix when you post your DTCs!!

 

NO DTC

Try this:

Manually shift the transmission thru the gears. If the RPMs increase smoothly in each gear, you may have a transmission issue. NO, Here, the car goes like hell

If the engine stumbles at the same point in each gear, its could be an engine issue.

Are you seeing any check engine lights OR flashing Check Engine Lights OR messages in the DIC when the problem happens?? No check engine lights or message

 

Please provide the following information:

Is your car modified?

If it is modified, what modifications did you accomplish?

Is your PCM modified or aftermarket tuned? If it is who tuned it?

Please expand the explanition on shifting the car manually thru the gears Do that make it perform better or is there no change??

Bill

 

Something is causing the transmission to stumble. Thats why I need to know if you have ANY modifications or have had the PCM tuned.

Have you changed the size of the tires, or added different rims or changed the differential gear size or torque converter stall speed??????????

Hopefully some of the A4 smart people can chime in. All my Corvettes are MN6 or MN12 manual gear boxes.

It sounds like there may be a problem with the shift solenoids in the valve body or the valve body its self or something is causing your shift points to change. I'm not that A4 savvy but understand how they work. I will ask a friend to take a look at the post and see if he can provide some A4 shifting advice.

 

intake exhaust are my mods
same tire, same stall

pcm tuned by a tuner..

 

1 to 2 to 3.
pedal to the floor, no symptom

only if i'm running .

from a dead start, no symptom

 

Well,,,,,,,,,,,,,,,, Your transmission shift firmness and shift timing are ALL controlled electronically by your Power Train Control Module (PCM).

The PCM takes a LOT of inputs and decides when the transmission should shift, how hard it should shift and when it should down shift.

Without knowing the tuning parameters that your tuner made for the transmission, its difficult to troubleshoot. See if your tuner can take a look at it and maybe retune it. Was it a local shop or did you get a mail order tune??

Give my TUNER a call or e-mail him. He has a brand new tuning tool that will allow you to get the VERY BEST TUNE available and tailor it to your car and your mods by E Mail!!!!!!
Its done thru EFI Live and he has a brand new version available that will allow you to use a wide band and make your tune 100%

Check out this post and page down to thread #11 and Chuck explains his new EFI Live AUTOCAL.

http://forums.corvetteforum.com/c6-s...e-choices.html

Corvettes of Westchester NY

Call for details. 914-332-0049
Chuck CoW


Let me know what you think.

Bill

 

today
its look normal
maybe 2-300RPM
look like DEAD spot

 

Good advice from a super smart guy!


Chuck is still hoping to get submerged by the way!





Bet CoW can help you. And if he can't he won't charge you a dime!

 

Has this been solved yet?


Give me a call.

Chuck CoW

 

solve... i dont think this is a big trouble,

its seems like a deadspot