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Pete
Pete, Mechanic
Category: Car
Satisfied Customers: 16688
Experience:  15 years automotive training and experience.
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740i: My car when I press on the gas accels and decel on its

Customer Question

My car when I press on the gas accels and decel on its own. What could it be?

Submitted: 1 year ago.
Category: Car
Expert:  Pete replied 1 year ago.
My name is XXXXX XXXXX I am a professional here at Just Answer. I noticed that your question was not getting a response and thought I would see if you still need help with this.

Is the engine revving up when you press on the gas pedal and then decelerating with your foot still on the gas pedal?

Is or has the check engine light come on or have fault codes been checked at all?

Let me know so we can continue,thanks Pete.
Customer: replied 1 year ago.

yes the revving goes up and down with the gas pedal steady.


No check engine light

Expert:  Pete replied 1 year ago.
O.k.,when the engine is running at idle with no gas pedal applied does it rev up and down then as well?
Customer: replied 1 year ago.


no pedal idles good. just a small miss when sitting still (idle)

Expert:  Pete replied 1 year ago.
O.k. as for the misfire here this may be caused by a spark plug that is worn or damaged or spark plug wire/boot or possibly fuel injector that isn't atomizing properly.These are the most common causes for this misfire concern and since I cannot see the vehicle to check it over these would need checked into/tested to locate which component is at fault and once the fault is located it can then be repaired from there to correct it.

As for the accel/decel issue with no check engine light this can indicate a possible fault with the accelerator pedal/gas pedal position sensor.This sensor sends a signal to the computer to let it know how much throttle is applied,if the sensor for this assembly is failing it can cause the engine speed to fluctuate like this here and not turn on the check engine light as the computer will think this is the way the pedal is being pressed and released.

The pedal signal would need checked and best checked with a scan tool that can monitor this vehicles computer data to see if the signal is moving up and down with the engine speed even with your foot applied steady.If the signal is moving around like this then most likely the pedal would need replaced (includes sensor).I have seen these pedals fail on several model vehicles with electronic throttle control like this here.

Thanks Pete
Customer: replied 1 year ago.

DO you have a pedal part #?


I have replaced these spark plugs before should I pull and see if one is bad? that would at least eliminate the plug issue.

Expert:  Pete replied 1 year ago.
Yes,you can pull them and see if the electrode (center piece/tip) is worn or corroded or if there is any damage to the ceramic part of it as well and if any damage is found then the plugs should be replaced or at least the affected spark plug.

It looks like you might be able to get the pedal travel sensor itself without the whole pedal although the part number below but be the pedal and sensor combined,my info shows part number 12721712009 to be the pedal travel sensor which is the sensor that can cause this issue here.It shows it to be around $400 and right at 1 hours labor to have replaced.

Thanks Pete
Pete, Mechanic
Category: Car
Satisfied Customers: 16688
Experience: 15 years automotive training and experience.
Pete and 5 other Car Specialists are ready to help you
Expert:  Pete replied 1 year ago.
Hi,

I am following up with you to see if you still needed help with your question you had asked.If my help didn't satisfy your question please let me know so we can continue.

Thanks Pete
Customer: replied 1 year ago.

Hey Pete,


I changed the pedal sensor, osv, fuel tank breather valve and it still goes up and down from 600-1000 rpms holding the pedal in one place. I also took back to shop to check timing and everything was spot on. Did a compression check on all cylinders 175-190. Could it be a fuel pump? Any ideas?

Expert:  Pete replied 1 year ago.
Did you have the engine checked over for vacuum leaks at all to see if there are any vacuum leaks present?
Customer: replied 1 year ago.

Yes no leaks and also did a smoke test

Expert:  Pete replied 1 year ago.
Are there any warning lights on on the dash for this issue at all like a check engine light?
Customer: replied 1 year ago.

The only check engine lights is saying to replace the secondary air pump under the bumper.

Expert:  Pete replied 1 year ago.
O.k.,this is a difficult question for me to fully answer from here unfortunately and I apologize for that.

I will have to opt out and put this question back on the list to see if others can help more.Don't reply to my last post here unless it is a last resort as it will keep the question locked to me.I hope you can get this resolved with ease.

Thanks Pete
Customer: replied 1 year ago.


Hey Pete,


 


haven't heard from anybody on this issue...Whats up?

Expert:  Pete replied 1 year ago.
In some cases some questions can be difficult to assist with without seeing the vehicle for testing and this may be the case here.We can leave this question on the list to see if others can assist more or I can send this to customer service to be closed if you like.It may be worth waiting a little longer to see if anyone else can assist.

Let me know,thanks Pete
Customer: replied 1 year ago.


ok. could this be a vanos solenoid problem

Expert:  Walt-mod replied 1 year ago.
Hi,

I'm a moderator for this topic. It seems the professional has left this conversation. This happens occasionally, and it's usually because the professional thinks that someone else might be a better match for your question. I've been working hard to find a new professional to assist you right away, but sometimes finding the right professional can take a little longer than expected.

I wonder whether you're OK with continuing to wait for an answer. If you are, please let me know and I will continue my search. If not, feel free to let me know and I will cancel this question for you.

Thank you!
Customer: replied 1 year ago.


Hi walt Mod,


Yes turn this start of this conversation to someone who wants to get it done.

Expert:  Walt-mod replied 1 year ago.
Thank you for your continued patience. We will continue the search for a professional for you.
Customer: replied 1 year ago.


Why does this question have a closed status on my email?

Expert:  cloe0626 replied 1 year ago.
Dose it only happen when you press the pedal
Customer: replied 1 year ago.

Yes please read my whole conversation with this issue.


Let me know

Expert:  cloe0626 replied 1 year ago.
It sounds to like the throttle cable is sticking
Customer: replied 1 year ago.

This car doesn't have throttle cables. Run on fly by wire.

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