hesitation when accelerating at low speeds

[rmedina]

Originally Posted by dynodon

I have noticed in three different 300C's a slight hesitation or lack of smoothness when accelerating gently to moderately from a stop. This goes on through about 30 mph, and maybe into 3rd gear.

It is somewhat like having a slight misfire, but I don't really think that is it. more like an ignition control problem?

Anyone else notice this? Is there a fix that anyone knows about before I start taking the car to the dealer.

I do not have AWD (2WD version) and it is just over 900 miles so far.

Don
Illinois

I have the samething. I even went to the dealer for it. The supervisor for the service techs told me it was the torque corverter. He said for some reason the folks at chrylser decided to have it "kick in" between 1st and 2nd. What this means? I have no idea..

Rmedina

[LoanWizard]

This may be a new serious new problem. My new 300C with 290 miles on it developed a low RPM vibration and groan when between 1500 and 2000 rpm. At first is seems like road noise and a hesitation in the engine but it happensd any time the engine idles down and you start to accelerate again I feel and hear the vibration, i.e. even on the freeway doing 65 if you take you foot off the gas and let the RPM drop. I can put my foot in it and it shifts great, I just can’t cruise. I’ve had it in the dealer for 5 days and they are scratching their heads and think it is a torque converter problem. I called an acquaintance that is a second-generation Chrysler Transmission specialist he just happens to be working on his dealerships general manager’s 300C that has the exact same problem as mine. He thought he had it fixed last week but it is doing the same thing again. He has sent a tech email into the Chrysler to see what’s up. After your comment about the torque converte I’m seriously upset that this may be a major flaw in recently produced 300C’s.

[Pappa Doc]

Hey all,
I have the same surging / lunging feeling as well. It happens under light throttle up to about 40 - 45 mph. I really noticed it when i put on my 22's and thought that had something to do with it but i doubt it. I think it is that I am feeling to car better now. I will drive it hard for a day or two and see what happens.

Blessings,

PappaDoc

[HEMEEE]

Dynodon, there is a procedure for the C that you can perform that reportedly improves throttle response. Some of us did it and did notice an improvement and some did not... I did.
Even if you don't feel this addresses your problem, it's good to refresh the info for the newbies or those that may have missed it.

Here is more info and the procedure courtesy of a post by Joey:

"The Accelerator Pedal Position Sensor (APPS) assembly is located under the vehicle battery tray. A cable connects the assembly to the accelerator pedal. A plastic cover with a movable door is used to cover the assembly. The APPS is used only with the 5.7L V-8 engine."


After changing the ECM it states:

"Turn key to ON position. Without starting engine, slowly press throttle pedal to floor and then slowly release. This step must be done (one time) to ensure accelerator pedal position sensor calibration has been learned by ECM."

If changing the accelerator pedal position sensor it states:

"Leave ignition switch ON for a minimum of 10 seconds. This will allow PCM to learn electrical parameters."

Here is the old thread: http://www.300cforums.com/forums/showthread.php?t=1664&highlight=throttle+response Good Luck!

[rmedina]

Originally Posted by HEMEEE

Dynodon, there is a procedure for the C that you can perform that reportedly improves throttle response. Some of us did it and did notice an improvement and some did not... I did.
Even if you don't feel this addresses your problem, it's good to refresh the info for the newbies or those that may have missed it.

Here is more info and the procedure courtesy of a post by Joey:

"The Accelerator Pedal Position Sensor (APPS) assembly is located under the vehicle battery tray. A cable connects the assembly to the accelerator pedal. A plastic cover with a movable door is used to cover the assembly. The APPS is used only with the 5.7L V-8 engine."


After changing the ECM it states:

"Turn key to ON position. Without starting engine, slowly press throttle pedal to floor and then slowly release. This step must be done (one time) to ensure accelerator pedal position sensor calibration has been learned by ECM."

If changing the accelerator pedal position sensor it states:

"Leave ignition switch ON for a minimum of 10 seconds. This will allow PCM to learn electrical parameters."

Here is the old thread: http://www.300cforums.com/forums/showthread.php?t=1664&highlight=throttle+response Good Luck!

Little confused here. Do you press the pedal slow or fast. The above quote states to go slow, but when you read some of the treads it tells us to press the pedal as fast as possible?

Rmedina

[jcsganga34]

Linda, thanks for the reminder. I had used the procedure back when it was first posted and it worked for me. I just had some work done where I had to reset my Windows and ESP programs. I did notice that the hesitation was back. I read your post this morning and I re-calibrated and the hesitation is gone . Rmedina, I slowly pressed the pedal and slowly depressed, it seems to have worked for me.

[HEMEEE]

You're welcome jcs, my pleasure

Originally Posted by rmedina

Little confused here. Do you press the pedal slow or fast. The above quote states to go slow, but when you read some of the treads it tells us to press the pedal as fast as possible?

Slow as jcs said, which is why I provided this, the accurate quote... slow and steady wins the race so to speak

[dkals]

I had the problem also. When the post first came out, it said depress fast & release fast. Spent the last 3 months driving with it hesitating. This morning I did the slow & slow process. Much better!!!!!!!!!!!!

[HEMEEE]

Glad it worked, it did for me too, and with so many new C owners joining since the original thread it bears repeating

Dynodon, jjs, cmego... let us know if it helps your situation.

[jjs]

Originally Posted by HEMEEE

Glad it worked, it did for me too, and with so many new C owners joining since the original thread it bears repeating

Dynodon, jjs, cmego... let us know if it helps your situation.

Acutally, I was looking for this thread so I could chime in!

Thank you, thank you, thank you!! Did the 'trick' Friday when I got home for work...my fiancee and I went driving around quite a bit Sat looking for acreage, etc. and I did notice a definite difference!!