Trew

iTrader: (1)

I've noticed a very slight RPM surge at around 47 MPH when the car is in 5th gear on my 5AT. This happens only when I'm cruising under very light acceleration.

The surging is constant at this speed, and I've noticed the tach fluctuating about 50 RPMs back and forth while it's happening. If I speed up to a higher cruising speed, this doesn't happen. It's only present in 5th gear at 47 MPH.

Has anyone noticed this? Any suggestions on what it could be? I've got 20k miles on my 05 TL with original tranny fluid.

msala524

iTrader: (3)

Disconnect the negative battery cable for 10 mins to recent the ECM. I'm not sure if that will do anything but try it to see if it helps.

BigJustin

That happens to me too.
Sometimes it even happens in 4th gear.
Anyone have anymore input?

stillhere153

iTrader: (1)

there might be a tsb for gear shutter or what not, seen something about it a while back

kjelly

I have the same thing; have you tried putting it in 4th gear?

I think your going just fast enough to induce an upshift, but not fast enough for the car to have a steady RPM...

TCM TL 05

I have a similar RPM fluctuation any time I'm going under ~48 mph in fifth gear. I think that our cars don't like being under 1,500 RPM. If I'm in fifth gear, I try to stay over 50 mph (unless I'm coasting) and doing that seems to prevent the RPM from going crazy.

Sal's Type S

iTrader: (1)

Could also be a sign of a failing transmission.

Trew

iTrader: (1)

Oh don't even go there!!!

erick3

can you define "surge"?

Trew

iTrader: (1)

RPM fluctuates +/- 50 every second.

erick3

^ and that's bad because...? like rpm fluxes up and down the rpm band ~ 50 rpms ish?

Trew

iTrader: (1)

It's not bad. In fact, I'm not really concerned about it. I was wondering if this is a symptom of a bigger problem.

50 RPMs, maybe a bit more. I wouldn't quite say 100 though. The concern is that the RPMs shouldn't fluctuate back and forth if I am putting steady pressure on the gas pedal.

Will Y.

We old-timers call this "lugging" rather than "surging"-- the car is at a point where it is one gear too high. OP is probably right at the shift point between 4th and 5th; the owner's manual has a table of the speed ranges at which the 5AT will shift gears.

Sal's Type S

iTrader: (1)

try holding it in a lower gear and at same speed see what happens. could be the torque converter unlocking and re locking. .Or slipping a bit. Is the mileage hi. My brother truck was doing this a few years ago doing 65-70 and flat ground cruising steady you could see the RPM fluctuate a bit and you could also hear the exhaust tone change pitch. Either way cant be a good sign, Maybe a simple oil change to transmission could take care of it..

swedrows

i have this exact same problem...i told the dealer about it, but as always, they could not reproduce it when i dropped my car off for some other work....and of course, when i was driving it home i reproduced it right away. mine is exactly the same, at 47mph the rpm's go up and down about 50prm at a constant rate. i haven't found a cure for it yet, but i am going to be replacing my spark plugs and getting a new battery (63,000 miles on my car, so i just got passed my certified bumper-to-bumper warranty). once that is done, i'll report back here to let you know if it fixed it or not. i am guessing it won't, but who knows. i am starting to find it annoying how some acura dealerships won't check a part if they can't reproduce the problem. i had mentioned to my dealership that i thought it might be a throttle problem, but since they couldn't reproduce it, they didn't even check the throttle cable or anything.

Oskar

I have the exact same problem with my 04 tsx. it is driving me crazy. I can't figure it out. I cleaning the Tb, changed plugs and changed Air filter. still there. Any updates anyone.

Trew

iTrader: (1)

I think this might be the cause.

Oskar

So nothing to be done? I am curios why I just started noticing this. I had the car for 80k miles. it is at 91k now. haven't done anything with the tranny fluid yet...

Tripnbeats

are any of your accessories on in the car where more electricity would have to be produced???

Oskar

maybe the seat heater other than that nothing else.

csmeance

as others have said, its the motor LUGGING.

The TL's motor doesn't produce much power at lower RPM's, like 1100 or 1200 RPM's. Imagine the amount of power needed to go 48 miles per hour, 100, 110? Well at those RPM"s the motor is putting out about 50 or 60 at most, and then the transmission has to constantly lock and unlock itself to keep the power there. Its a design flaw, the TL should never be under 1500 RPM's when driving, the PC's should be updated to prevent that.

jackson615

I have this exact same problem with my 05 at about 45 MPH but only on a flat road. It has never "surged or Lugged" at any other speed. My 05 has 38k and Im thinking its a tranny problem not just Acura normal behavior.
But you guys know more than I but I am getting tired of hearing and feeling the car "surge" at that speed.

"swedrows"
if you encounter this problem again take it to the dealer and see if the mechanic / tech can ride with you cause your driving tendencies may be different that his therefore the car will react differently.
just my .02 on that.

"csmeance"
so are you saying that this is normal/ common problem with the TLs or what?

csmeance

It is a problem with every TL, there isn't enough power to move the car under 1500 RPMs thus causing the revs to fluctuate.

jackson615

Thanks for the help "csmeance" cause I was starting to think I got a lemon or something.

Oskar

i understand and most definetily appreciate the feedback. What I can't get my arms around is that, why did I just started noticing this? I pay very close attention all things that go on with my car, and this one I would have definetily noticed. Any thoughts if this maybe related to o2 sensors or fuel delivery (injectors, sensors etc)? Again, I appreciate the feedback but I found it hard to believe this always existed in the car.

gshantanu

I have this exact problem in my 2nd Gen TL. Just thought I'd mention it here for the sake of 3rd Gen TL owners. The RPM fluctuates for all fixed speeds b/w 40 - 70 MPH. The fluctuation is very clear, and I can both feel it and see it on my tach.

I agree with Oskar and others that it was not something in the car's original spec. I have the car for so long, and this problem just started 5 months ago. So, definitely there is a clear (but unknown) cause for this anomaly.

I have tried replacement/cleaning of: spark plugs, ignition coils, TB, trans oil, seafoaming. Nothing has worked so far.

My current hypothesis:
1. Some vacuum leak somewhere (very minute) and manifests itself at certain vehicle operation points only.
2. Torque converter is dying. There is no problem code, so no way to find this out.

Has anyone been able to successfully solve this issue?? Thanks.

I hate cars

I doubt it's lugging on the 5at. It only takes about 35hp to maintain a steady 45mph. Mine pulls 1,500rpm easily in 5th gear without any of this surging.

To eliminate it, put it in 4th at the same speed and see if it still does this.

It could be the TCC not being able to make up it's mind to lock or unlock. Sounds more like a programming error than anything else.

There's a threshold where the TCC is supposed to lock. Some are programmed to only lock when you're above say 10% (a guess) throttle. You may be right on the edge of this threshold. All of them unlock when you let off the gas and most unlock when you're at WOT.

Either way, 50-100rpm difference under light throttle sounds about right for the TCC to be locking/unlocking.

gshantanu

Thanks for your input, I-hate-cars. Let's say we go ahead with this hypothesis that TCC is locking/unlocking. Can we:

1) confirm this suspicion by doing some simple test/diagnosis procedure?

2) fix it using TCC reprogramming (if possible) or replacement?

Of course, I would like to confirm first before doing something dramatic (like replacing TC). Just to let you know, I have reset my ECU a couple of times, and that does not help.

I hate cars

The easiest diagnosis is to drag the brakes as lightly as you can. Push them just hard enough for the brake lights to come on but not actually slow the car. This will prevent the clutch from locking. If it goes away, you know it's the clutch locking and unlocking.

As for the treatment, it sounds like bad programming, maybe there's a reflash out there.

gshantanu

Today I tried to do some diagnosis. I didn't even have to go as far as dragging on the brakes. As soon as I leave the throttle, the RPM fluctuation goes away. So, the problem occurs only when the throttle is lightly pressed, and I am going at a fixed speed. And all this happens after the vehicle gets semi-hot..(20-30mins of driving).

Did you want me to try to push the brakes along with the throttle? I did not try that..but I right now believe that it is a TC locking / unlocking issue.

I hate cars

Whenever the computer sees that the brakes are on, it disengages the TCC. Try not to actually drag the brakes, all you're trying to do is send a signal to the computer that the brakes are on. Do the bare minimum braking to make the brake lights go on. Once the brakes are on, drive exactly how you were to make the symptoms appear. If they don't reappear, you know it's the clutch locking and unlocking.

ssmtl2nv

iTrader: (2)

Ive had a similar situation, just stay above 1500 rpm...

gshantanu

Got it. I'll try to give a small nudge to the brakes, while holding the throttle steady. If the problem disappears, then we'll know its TCC.

Thanks again guys, I am not that worried cause my performance hasn't suffered one bit, but it is just annoying at times.

vannakam

i have the exact same problem with low rpm on my 2nd gen TL... but im guessing it might be the o2 sensor

1fsthatch

now the question is did this occour when you first bought the car

vannakam

nope it happened starting of winter... but the funny thing is.. it surges in D5 gear.. and the rpm is low.. it hesitates as soon as u push the gas pedal and the rpm doesn't go up it stays still struggling.... and in D4 gear the rpm is very low.. like say im driving 60km/h the rpm is at 1,200RPM and you can hear the engine growling inside the car .. so it's weird.. could be one of the coil packs or the o2 sensor.. i got the EGR valve replaced, cleaned the ports, changed the OEM plugs from Acura.... it's very annoying..

vannakam

and by the way .. my gas mileage is crapp...

CUCU28

iTrader: (4)

I have had the same problem and after alot of reading post on every web site and going to 3 dealers that told i need a new tranny. I figured it out and i have fixed the problem. It is part number 37971-rbb-003 119.36$ replace this sensor and your problem is solved. The sensor is located on the passenger side under windshield it has a cable running across from the drivers side pedal. I just did it and it fixed the problem instantly. Take care guys

ricesmith

I see there have been no more replies so I hope that this worked because I notice that my 2005 TL is doing the same thing now. I will replace the part unless there has been more developments since the last post.

GerryK

Have you replaced the part and if so, did it fix the problem?