Problem with Bad Accelerator Response

[346sfi]

Looking for input on the following problem (or if there is already a thread on this issue will appreciate direction to it):

When I start from a stop there is a “dead spot” in the accelerator so that there is a hesitation before power comes in. This happens no matter what revs I start out at. If a soft launch then there’s a hesitation that feels like you are lugging the engine before power comes on to smooth out acceleration. If a hard launch followed by immediate full throttle its still bogs down before full power comes on.

All of this only happens when starting off from a stop (1st Gear)

I do NOT have this issue with accelerator response when upshifting into 2nd through 6th . No problems either if I downshift and get on the accelerator pedal – instant response.

What cause should I be looking for? (I have cleaned the throttle body including the back of the TB plate as suggested by a factory engineer at NCM last fall but that did not help).

This is a 2003 Coupe -- LS1 with T56 trans and no mods.

Thanks.

[vettex2]

any codes ?

[346sfi]

Originally Posted by vettex2

any codes ?

Only codes are:

A0-LDCM - Left Door Control Module - U1064 H (Loss of Communications with BCM)

A1-RDCM - Right Door Control Module - U1064 H (Loss of Communications with BCM)

[vettex2]

Well those have nothing to do with it.....

[stevebz06]

I had a throttle position sensor go bad without setting any codes.

[coolvette]

Has something to do with "torque management" from what I understand all C5 6sp manuals have it. It is programmed into the computer and it is designed to do exactly what you are experiencing. Basically, it will not allow full engine power to the drive train until there is an even amount of torque applied all the way back to the rear wheels. To the best of my knowledge, there is no way for the driver to turn it off but I think you can turn it off by using one of those "tuner software" modules but I'm not too sure on that one. Maybe some one else can further comment on that one because I am looking for a way to turn mine off on my 2000 6sp manual. Hope this helps.....

[ToolGuy]

This does not sound normal to me. My 98 6-speed does not do this i.e. at a normal start, or when I stab the throttle.

What happens when you down shift, hold the RPMs on the high side, and then lay into the throttle?

[346sfi]

Originally Posted by ToolGuy

This does not sound normal to me. My 98 6-speed does not do this i.e. at a normal start, or when I stab the throttle.

What happens when you down shift, hold the RPMs on the high side, and then lay into the throttle?

No problems when I downshift and get on the accelerator pedal – instant response. The condition I am concerned with happens only off idle. I have since gotten ahold of the 2003 shop manual and it of course has an entire doagnostic sequence to go through from clogged fuel filter to PCM ground check, MAF leak, dirty air cleaner, TPS, etc. etc. I just wondered if from someone elses experience there might be a likely area that occurrs more than others to cause this condition so I could narrow down what I am to look for.

Thanks.

[c4c5specialist]

HI there,

Unfortunately, the data is key.

I would be monitoring torque requested, TPS, APP and see if they all correlate.

A Tech 2 will be necessary.

Unfortunately, there is nothing via internet that can tell you what because there are so many factors to throttle response.

I would be curious how long this had been occuring, what was the mileage when it started and then check the data from there.

Allthebest, c4c5

[346sfi]

Originally Posted by c4c5specialist

HI there,

Unfortunately, the data is key.

I would be monitoring torque requested, TPS, APP and see if they all correlate.

A Tech 2 will be necessary.

Unfortunately, there is nothing via internet that can tell you what because there are so many factors to throttle response.

I would be curious how long this had been occuring, what was the mileage when it started and then check the data from there.

Allthebest, c4c5

Thanks Paul. After getting hold of the 2003 Shop Manual and reading the diagnostic sequence for "Hesitation, Sag, Stumble" I see that the diagnosis of this problem is beyond my DIY capabilities and tools. I understand why you say this is not a probelem with an easy internet answer but do as always appreciate your response. To answer your question, my '03 is currently at 32,000 miles. This is an issue that has kind of snuck up on me (I think I had been uncounciously adapting to the problem by moderating launches) but seems now to be more pronounced -- or I am more aware of it. Based on the mileage I put on per year I'd guess it may have started as long ago as 27-28,000 miles.

Best regards.