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John
John, triple chrysler master tech
Category: Chrysler
Satisfied Customers: 2251
Experience:  43 years,triple chrys ,ase master tech,l1,t2 b5 a1-a8 Hev spec.
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2005 Pacifica: 3.5L..slightly downward roads the car seems to surge

Resolved Question:

I have a 2005 Pacifica w/ 3.5L engine. While driving at constan speed on level or slightly downward roads the car seems to surge. It feels like what you could do if you applied the brake at the same time as you press the accelerator pedal and then release the brake just slightly before you release the accelerator pedal. The engine idles great in Park, runs fine above ~45 mph and as long as you are accelerating or decelerating between 0 & ~45mph it runs/drives fine. Any ideas what this might be?   I suspect it is the transmission because the engine runs fine. Its almost like it want to change gears but a soon as it starts to it decides not to and that cycle continues to repeat until you decide to accel or decal a little. Thanks for any advice.
Submitted: 7 years ago.
Category: Chrysler
Expert:  John replied 7 years ago.
Hi my name is John.

Does it do this if you put the car in a different gear like 3 or 2?
Customer: replied 7 years ago.

Its been awhile since it was playing with putting the trans in a lower gear so will need try that again before I could say for sure. Its my wife's car so will not be able to try it again until this evening. This is my 1st time on this site can I log-on and send you an a reply later this evening?

Expert:  John replied 7 years ago.
Just come back to this question.

You can answer me by doing that.

John
Customer: replied 7 years ago.

Last evening it ran pretty well with very little surging while in Drive. There did seem to be a slight surge when tested in 2nd, 3rd & 4th gears. It hasn't worked this well in several months. Still curious for your opinion.

Expert:  John replied 7 years ago.
If it is the overdrive tring to engage it will cause this problem some times.

The throttle position sensor and the map sensor can also cause this problem.

Does it make any different if the gas tank is between 1/2 and 5/8 of a tank of gas?

You can also try wiggleing the TPS connector up and down just a little bit to see if the rpm will change.
Customer: replied 7 years ago.
The fuel level hasn't been a factor, the surge occurs at all levels. My original thought was that the torque converter was trying to lock up but didn't think it would do that at the low speeds. There are no trouble codes so I was less inclinded to suspect sensor problems. What would fuel level between 1/2 & 5/8 have to do with this symptom? When I take this in for service what do you recommend I tell them or make sure they check 1st before they tear in to the $$$$ transmission? Its out of warranty.
Expert:  John replied 7 years ago.
The 1/2to5/8 fuel is a software flash for not running right.

Before i would replace the torque converter,I would replace the throttle position sensor and map sensor first.Because they can cause this problem also.

I would have the computer updated with new software and have them test the map and TPS frist.

Let me know what else you want to know.

If i have help you,please push the accept button when were done.

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