hesitation when accelerating at low speeds

[jjs]

I know I was already the last one to reply to this thread, but wanted to move it up the 'active' list once more to strongly suggest this 'fix' to those who have not yet tried.

[LWOOD]

I had done this way back when the thread was first reported and noticed no real difference...I did the pedal fast, not slow and did not wait until all initial warning lights went out. This time I did it like the thread said, and WOW. I feel like I have a brand new car. Of course, fuel economy is suffering a bit from my newly heavy foot!

[jjs]

Originally Posted by LWOOD

I had done this way back when the thread was first reported and noticed no real difference...I did the pedal fast, not slow and did not wait until all initial warning lights went out. This time I did it like the thread said, and WOW. I feel like I have a brand new car. Of course, fuel economy is suffering a bit from my newly heavy foot!

Exactly my feelings!

[HEMEEE]

Still wondering if it worked for you dynodon??

[HEMISKI]

i tried the accelerator pedal depression deal many times and here are my results, if anyone is interested, ofcourse!!.....
very slowly down and very slowly up...i got more of a delay , especially punching it from 30mph, and seemed very erratic and jerky.
fairly quickly down and equally fast up (about 1 second for down and up combined)...results were fantastic, better throttle response, nice and even acceleration, felt a little more powerful, and im far more comfortable flooring it, knowing it wont jerk the revs too much.. Just my findings. OH, i did wait for the instrument lights to go out b4 i pressed accelerator, then waited 10 seconds after pressing, then turned off, then restarted immediately .

[Nor300Cal]

This was quietly making me insane . I thought honestly it was just me and had resolved to the fact that it might just be the tranny or the MDS kicking in and out. Oooohhh so wrong! This fix definitely works . My hesitation or slight lunge from a stop is completely gone. I only drove it for about 5 minutes, but it feels distinctly different. If I WOT it from D I don't feel a difference...it's always been fast. But if I go through the gears it feels slightly quicker and definitely smoother. Thanks to who found the fix...and thanks to all of you who passed it on .

Kevin

[ResumeSpeed]

I'm not sure if this TSB will specifically address anyone's "hesitation" problems but since the TSB title just specifies Trouble Codes and relates to "cold" hesitation problems I thought it might be worth posting. Note that this applies ONLY to early model 2005 builds per the dates listed below.

TSB #: 18-031-04 REV. A

Date: November 12, 2004

Group: Vehicle Performance

MODELS: 2005 (LX) Chrysler 300/Magnum

Subject: Flash: Driveability Improvements MIL Illumination Diagnostic Trouble Codes P0116, P0139, P0159, P0197, U110B or U1402

Overview: This bulletin involves selectively erasing and reprogramming the Powertrain Control Module (PCM) with new software.

NOTE: This bulletin applies to vehicles equipped with a 5.7L engine (sales code EZB) and domestic market emissions (sales code NAS) that were built:

- On or before May 28, 2004
- Between July 1, 2004 and August 18, 2004.
- Vehicles with a 5.7L engine built on or before June 12, 2004 or between July 1, 2004 and August 18, 2004


Symptom/Condition:

This bulletin addresses one or more of the following conditions:

1. Eliminates stumble and hesitation when aggressively/quickly shifting between reverse and drive following a engine start-up.
2. Rough Idle after a hot start.
3. Long crank times on hot starts.
4. Intermittent oil pressure light illumination and chime while accelerating from a stop.
5. Improved shifting at low vehicle speeds.
6. Following a cold start, the coolant gauge stays at “C” cold and does not follow the increase in coolant temperature, with a TCM DTC U110B - Lost Engine Coolant Message or U1402 - Implausible Engine Temperature Signal Received or a PCM DTC P0116 - Engine Coolant Temperature Sensor Performance set, and the cooling fans running continuously. A key cycle would resume normal operation but the DTC will remain set.
7. Improved fuel economy for European NA1 emissions.
8. MIL illumination for DTC P0116 - Engine Coolant Temperature Sensor Performance.
9. MIL illumination for DTCP0139 - O2 Sensor 1/2 Slow Response.
10. MIL illumination for DTC P0159 - O2 Sensor 2/2 Slow Response.
11. MIL illumination for DTC P0197 - Engine Oil Temperature Sensor Circuit Low.

NOTE: To further improve shift performance it may be necessary to reprogram the Transmission Control Module (TCM) with new software. Perform Service Bulletin 21-009-04.

[dynodon]

Hemeee, Just saw the new replies and will try the reset procedure today (5-1) and report back.

Again, I think the response to input is fine on my car, and shifting is fine, just slow steady accelleration results in noticable but not terribly annoying variation in speed as the car speeds up. Steady speed = no problem, lots of acceleration = no problem.

But I will try it and see what happens.

Thanks everyone
Dynodon
Illinois
300C Magnesium

[dynodon]

Tried that reset procedure and I think it helped. I don't notice the variations in speed when pulling away from a stop as much as before. Almost totally gone.

I turned on the key, waited till every light except the engine indicator (don't think it ever goes out till you start the engine) then slowly floored the accelerator pedal and let it back up.

Drove it several times today (Monday) and didn't notice the sensation of the car not knowing what speed to go.

Thanks for the tip, and I will report back if it comes back.

Dynodon
Illinois
300C Magnesium now a little smoother away from the stop.

[HEMEEE]

Originally Posted by dynodon

Tried that reset procedure and I think it helped. I don't notice the variations in speed when pulling away from a stop as much as before. Almost totally gone.

I turned on the key, waited till every light except the engine indicator (don't think it ever goes out till you start the engine) then slowly floored the accelerator pedal and let it back up.

Drove it several times today (Monday) and didn't notice the sensation of the car not knowing what speed to go.

Thanks for the tip, and I will report back if it comes back.

Dynodon
Illinois
300C Magnesium now a little smoother away from the stop.

That's good news, so far it seems to have worked for everyone that tried it. BTW, the hesitation never came back for me, but according to jcsganga34, he did have to do the procedure again after some other system re-sets... something to remember if the symptoms reappear - it's sure a simple fix!