RPM drops when accelerating lightly after a stop

toyota
corolla

#1

2009 toyota corolla, 55K low mileage. RPM drops ONCE , usually when it hits somewhere between 2K and 3K , it drops a little , like 200-600 i believe. and then it becomes normal and goes up smoothly like nothing has happened. When the RPM drops , the car feels jerky. This problem happens when accelerating from a stop and is less severe after i cleaned the mass air flow sensor. And it does NOT show up when trans is put in “L” , it is less noticeable when put in 2, but noticeable when put in 3-D. Transmission fluid is pink and clear and NOT low. Car also tends to surge forward a little when coming to a complete stop. Other than these, the car runs great.


#2

Thats the a/c compressor kicking in.It does the same thing on my 2012.The rpm rises when the a/c compressor kicks in and its normal. Keep your foot on the brake whenever you are stopped to prevent the car from surging forward when the a/c is on.


#3

Thank you very much for your reply.


#4

about that RPM drop issue, i used a scanner to check live data, short term fuel trim always stays between -5.5 to 6 and long term always stays between -3 to 4


#5

.RPM always higher when engine is cold but will drop and stabilize when engine warms up.


#6

http://www.automotiveforums.com/t216675-rpm_drops_while_accelerating.html

this thread is about the same problem , some interesting insights there.


#7

Could be a problem with the throttle position sensor. See how it works on this video


#8

Thank you for the reply. I can’t understand why it doesn’t happen, I mean the rpm drop, when I put the car in low gear


#9

I rarely use the low gears on my 2012 unless I need engine braking when going down a steep hill.I use D3 all the time.I never noticed rpm drop because I don’t always look at the tachometer when choosing the low gears but I will try that next time I drive it.I will post back the result.


#10

Thank you, I meant low gear driving is fine, but D3 gear and 2 gear are NOT OK, will show rpm drop when accelerating.


#11

Are you sure you are not seeing the RPM drop as the transmission shifts gears? because that is normal. Only with a CVT does this not happen.

D means the transmission goes through any number of gears until it reaches cruising speed. could be 2 shifts, could be 8.


#12

@Guang_Yang Did you just acquire this vehicle ? Because RPM’s dropping during acceleration just does not sound right. Do you have anyone who can drive this thing and maybe give a better description .


#13

Yeah, i got my car not long ago. i didn’t pay attention to the RPM drop when i test drove the car, it didn’t feel jerky if you accelerate normally, i mean the RPM still drops but you don’t feel the car jerk when you are heavy -footed on the gas or like normal. But when accelerating slowly from a stop , it’s quite noticeable that the car jerks. I asked a mechanic online who has given me good advice in the past that, he believes it is the transmission, the torque converter, he suggests i get the trans fluid changed and add lubegard in black bottle too because "The problem is the transmission fluid is to thin and the lock up converter is not staying locked up. "


#14

I just got an obd scan tool, i will figure out how to use it to diagnose my car.


#15

It could be the torque converter lockup clutch not working smoothly.
I suggest drain and refill the transmission fluid, and see if it improves.