I just bought a 2004 a few weeks ago and absolutely love it. I have noticed one snag though, when going about 30mph and flooring it, sometimes it does not kick in right away. Occasionally the car will just increase in speed slowly and then "catch" and take off. Other times it will immediately jump out and throw me back in the seat as it should. What should I be looking at for this intermittent problem? I only use premium gas and as I stated, most times it will react correctly. Your help would be appreciated and thank you in advance.
Mark

 

Auto or m6, make sure that you have done a complete tune up check fuel pressure

 

It is an automatic. I have not had it tuned up as of yet. What should the fuel pressure be and how do I check it.
Thanks

 

You will hear allot about ways to increase throttle response while on this forum. I think you may benefit from doing a few easy modifications.

Do you have an intake? Or even a high flow filter? Removing the throttle and cleaning out all the years of gunk from it and inside the intake will help allot too. Performing the throttle body bypass will densen up the a/f charge a little and help too. Then if you really want a big difference, port and polish the TB, buy an intake, upgrade the air bridge etc.

These will make a clear difference in that "woosh"noise you hear when the car is gasping in allot of air. The more air and quicker you can get it in, the faster the car will power up.

 

Where are you located??????????????????????

 

This sounds familiar my 98 c5 had the same hiccup with I WOT, recently did a LT headers swap an eliminated cats, problem went away. Prior to that I cleaned my MAF sensor and tb and added after market air bridge and filter, problem was still there. After takin out the cats and intermittent prob went way at wot without even a tune yet, so I'm guessing it was a catalityc converter going bad. Slowly start eliminating possible problem areas start with smaller easier fixes then to the bigger ones such as the cats

 

I am located in NC

 

a mail in tune to set and firm the shift points would work wonders.
plus aren't the autos geared really high so take off isnt that great?

 

Not sure what a "mail in tune to set and firm the shift points" is. Sorry, but some of these terms are still outside of my expertise. Learning as I go. How is this done?

 

Cool

You have two choices.

1: take it up to Va Beach to VASPEED. Near the south gate of Oceana Air Naval station

2. Vanceboro NC, a little known but great tuner and engine builder lives down there

Call Wiliam at 252-670-7706

tuning is the key to eliminate throttle lage

 

I think this is how all automatics are set up. In my 04 A4 I thought it was a problem too but I think its how its made. If I go 35 or under and go WOT it will ALMOST always jump up to 5500 and go like you want but if you are going 40 or over and floor it it will not accelerate hard and only jump to around 3000rpm. Im not a huge gearhead but yeah a different rear or tune could change the shift points and make it work but I don't think there is anything wrong with the car you just have to go by your speed (not rpm) and hope it downshifts. Anyone wanna confirm?

 

An automatic is an automatic. Even after all the fine tuning and modifications Ive done, I still experience this from time to time. Its just then nature of the beast. An automatic cannot be controlled like a manual. There is plenty of room to make it better, but sometimes it just does what it wants to do.

 

100% Nows a good time to get any bolt on mods accomplished.

Recommend install:

VARARAM
Long Tube SS Headers XS Power can be had for a reasonable price and perform outstanding.

If you dont want to or cant MOD at this time,,,
A good TUNE will get you better transmission performance and proper shift points.

Bill

 

Thanks Bill, sounds like a tune up is the place to start. I appreciate all the help everyone has given me. I may be asking some questions that seem obvious to all of you but as a new C5 owner (actually new to the performance car arena in general) I have a lot learning to do.
Thanks everyone
Mark

 

Mark

Before you get too excited,, A good in the the Shop Professional PCM retune is Approx $400-$500 regardless if you have Mods or not.. That is why most people tune after making all the bolt on mods that they can afford..

You have other options. You can get a Mail Order tune which is accomplished by Removing the PCM and send (MAIL IT) it to a tuner of choice.
The Tuner will flash in his brand of PCM tune that he find works the best for your C5. Seeing that you don't have any Mods,, the tune will make good improvements but with marginal HP increases. You will see more transmission shift improvements than HP increases. Most mail order tunes are around $100$150.

That is why I recommended that you install all the Bolt on HP improvement MODS that you can afford to do before you tune it. Every time that you add something, you DETUNE it a certain amount which will effect the engines efficiency...

You can also find a tuner that uses something called INTUNE or AUTOCAL. You purchase a module that plugs into the ALDL connector under the dash and use that module to collect PCM data (DATA LOG ) on how the engine performs. You send that data back to the tuner via e-mail and he builds you a PCM Calibration that is more accurate than a general mail order tune. You use your home computer to transfer the collected tune data to and from the tuner and upload that new calibration that the tuner builds for you to the PCM via the AUTO CAL module. The good part is you can have the tuner recalibrate the PCM when and if you make MINOR MOD changes to the car/engine. NOTE.. Most tuners will charge you to make MAJOR tuning changes. IE New Cam, heads or different injectors. ,,, etc...

Another route is: You can purchase a hand held tuning device like Predator or Superchips BUT,, they can only make limited PCM modifications. They work better on cars with Automatic Transmissions because they change more A4 functions than engine calibration functions.. You have to figure out what tune calibration changes you want to make to the PCM..


Note! An in the shop professional tune uses a wide band O2 sensor to adjust critical PCM operating parameters and to adjust the WOT Throttle (PE) air Fuel Ratio which is critical for the most power.

That type of tuning is more accurate, requires more shop time to get the PCM calibration right and that is why its more money. Some Tuners use a dyno, Some tune the car on the street and some do BOTH.

PM SENT!

Bill

 

with Bill

 

Getting rid of torque management will solve most of your problem.

 

mine does the samething and its tuned. it has to do what the mph at 25 or 35 it will down shift but at 30 it doesnt like to i think it wil around 32 also wasn't looking, but we dont have a 30 or a 50 pull. so if you plan on a highway run against someone try to get at least a 60, starting at 80 isnt to bad either and i have 2.73's a stall will help that out alot i just ordered a yank ss3600 and get some 3.42s it will feel like 50 extra horsepower.

 

sounds like torque management in the tune

 

Pull the PCM, (computer behind pass. side front wheel) out and send it to Corvettes of Westchester. Chuck can recalibrate it and make a huge difference. Don't expect to be able to burn the tires off, though, with an auto.

Enjoy the ride!