M45 problem downshifting?

[Wesamalmahdi]

HI Guys!

Im new to the forum so please allow me to introduce myself. My name is Wesam and I recently purchased a 2009 Infiniti m45 the car is amazing firstly. It has 108k and is a pleasure to drive. However, after a long road trip to new york and back recently I started noticing something. When I release the gas pedal and just try to coast, whether at high mph or low the car almost feels like the brakes are being applied or if its downshifting. the rpm needle would go up a little bit and then come back down exactly like its down shifting. Im not good with cars and I dont want to get scammed by mechanics. Can someone share some insight on this? maybe you've experienced this before or something. Thank you all in advance.

[Ilya]

Welcome to the forum.

Do you have any check engine codes, etc.?

[Wesamalmahdi]

Welcome to the forum.

Do you have any check engine codes, etc.?

Hi there! No i dont have any codes on dash thank God.

[Ilya]

It sounds like your car is engine braking (totally normal) but we need to find out why. How fast were you going when you experienced this? Were you in manual mode or regular mode (shifter)?

[Wesamalmahdi]

i actually never used sport mode. Im always in automatic. Just when I got back I started noticing it. As soon as I release the gas the car just slows down exactly like a downshift or ifnthr brakes are being steadily applied. It does it consistently regardless of speed but at certain mph you noticed the needle jerk up like going down in gears and then immediately settling back down. Other than that the car is super smoothe

[Ilya]

How much throttle are you giving before it happens? Cruising? WOT?

[Wesamalmahdi]

Im sorry to seem ignorant as i know little to nothing about terminology. But when yiu say throttle do you mean how much pressure i apply on the accelerate pedal? If so then different amounts. It doewnt matter how much it, it happens whn i let off the gas and try to "coast". Car just slows down but in a way that resembles braking or downshifting.

[Costee]

Welcome to the forum.

Do you have any check engine codes, etc.?

Hi there! No i dont have any codes on dash thank God.

Actually, it would have been more preferable to have codes on the dash. That way you know what the problem is. That said,not all codes are represented on the dash and you'd need a dealer-lever scan tool to read such codes. Maybe with time a code might prop up.

[LIBRILZ]

You certainly have a rare issue unfortunately. It is normal for the car to go to a lower gear if going up a bridge, or taking a corner, but you shouldn't feel a great amount of resistance in just trying to coast

[Ilya]

It's possible that perhaps your brake calipers are sticking which is causing 'drag' on your drive...however, that wouldn't explain the RPM needle dancing or blipping when the car downshifts...unfortunately, without a code or something else to go on and being we can't see the car ourselves...you may have to take your car to shop and have them give it a look over...

Unless someone else here can come up with something else.

[EdBwoy]

I have to ask, does this happen when you use cruise control with other cars around you?


It is also possible your car still needs time to shed its transmission learned behavior. Maybe it was usually driven quite aggressively before being sold.
Try to reset the computers. One way is to disconnect the negative battery terminal overnight or using this procedure - m35-ecu-reset-t529045.html
You will most need to reset your auto/one-touch windows and sunroof afterwards.[owner's manual - instruments and controls - section on Windows]

[Wesamalmahdi]

Thanks for all the help guys. Yeah i tried coasting on neutral and it went just fine, no rpm dipping or that sensation. I will try to disconnecr the negative battery terminal tonight hopefully it helps. And it does feel like there is some drag on acceleration too perhaps i should have the brakes inspected.

I did so much research on infiniti I dont recall any transmission problems popping up so I hope it isnt that.

[EdBwoy]

I have to ask, does this happen when you use cruise control with other cars around you?
...

So, cruise control or no?

[Wesamalmahdi]

Oops sorry my friend i forgot to respond to that part. I also have not used cruise control at sll in this car i will try it on my way home from work tonight God Willing. I dont assume it would do it because it only happens when foot is off the gas.

[EdBwoy]

Ok, cool. I was curious (if you had intelligent cruise control) if the car was braking due to perceived obstacles. Try the reset, and let us know if it improves at all.

[FlawleZ]

I think I know exactly what Wesam is describing because my car does it too. In fact, I bet they all are doing this and you guys aren't realizing it.
When you let off the gas pedal and leave the car in gear (drive) at speed the car remains in that gear causing a slight engine break scenario. You further see this by looking at the rpm when you let off then put the car in neutral and you will see the RPM fall to idle when in neutral only. In fact, it's been said by others in the past if you are just coasting downhill it's more gas efficient to put the car in neutral as it will move freely down the road instead of the trans having a constant subtle drag.

[Ilya]

I think I know exactly what Wesam is describing because my car does it too. In fact, I bet they all are doing this and you guys aren't realizing it.
When you let off the gas pedal and leave the car in gear (drive) at speed the car remains in that gear causing a slight engine break scenario. You further see this by looking at the rpm when you let off then put the car in neutral and you will see the RPM fall to idle when in neutral only. In fact, it's been said by others in the past if you are just coasting downhill it's more gas efficient to put the car in neutral as it will move freely down the road instead of the trans having a constant subtle drag.

Engine braking is normal. Some cars do it more than others. Same as motorcycles. In fact, when I'm riding my motorcycle in the back roads, I hardly ever use much break. I downshift and let the bike do its job and enter the corner at optimum speed.

Also, I wouldn't put an automatic in and out of gear while moving. But that's just me. I get the 'no drag' part but automatic cars weren't intended to be used that way...unlike manual cars.