Just as a test, since it happens only when starting from a stop, when it occurs, try manually downshifting to 1st. My initial suspicion would have been the transmission, and I'm wondering if it is not properly downshifting to 1st at a stop. If it were still in 3rd or 4th, it could be that it is just lugging the hell out of the motor at that speed. Or, when it occurs, if you let completely off the gas, and then re-apply, does the problem subside?

You said if it is happening and then you put it in neutral the problem goes away. That leads me to think its just abnormal load on the engine. I dont know a lot on how the electronics of these autos operate, but if they are like most Honda automatics, they are close to 1930s tech.

 

I noticed the problem will still happen at normal driving.. just not as prominent because the load isnt as much as from a stop. I have tried the manual shifting and it is always in the right gear. I wish I could upload a sound clip of the change in sound.. you guys would be surprised at the difference.

Normally the only way the problem will go away is a longer drive at highway speeds or letting the car completely cool off overnight.

 

Can someone just permanently lend me a new 3.5? Thanks...

 

Still nothing a ?

Why dont you unplug the VSA fuses and drive it like that for a day or two to see if you can tell any difference.

 

I have already tried that and it still happened. Did it for 6 days with no VSA fuses.

There is either a vacuum leak or something with my fuel system. Those are the only things that will make my car backfire and pop alot when the problem is happening. No CELs still.

 

Have you smoked any of the vaccum lines to test for a leak?




in my s4 when it would develop vaccum leaks ( at least the times it did leak ) it would go into limp mode which is similar to the problem your encountering. Although the problem wouldn't be intermittent.

 

I have not. I just didnt think it would be a vacuum leak if the car idled fine, and the problem was intermittent. I was thinking something a little bigger picture like losing vacuum at the head or something along that lines. Maybe the block is getting heat soaked and then letting in un-metered air.

 

trade this thing in! i feel bad for u

 

Acura offered to pay it off if I got into a 2014 TLX, or TSX. I don't ever want another Acura to be honest. They wouldn't even test my fuel pump for me. They told me if it was a fuel pump, there would be a CEL. They are literally just throwing their hands up because of the intake/exhaust and no CELs.

Everytime a new mechanic looks at it I get "Well I notice you don't have cats on the car, the engine is designed to run with cats". The most BS thing ever.

 

Is my throttle plate supposed to have play in it? I can move it about 3/4'' before it actually has some resistance.

 

So I took it again today to the dealership and low and behold the technician was able to duplicate the issue. He said "the car completely falls on its face then just randomly gets back up and takes off". They did the ECU software update with no effect. He took 3 or 4 snapshots while the problem was happening and is sending them off to CA to get evaluated. I got charged again 119$ for diag though. FIrst he blamed it on my o2 bungs that are on the PCDs. Then he tried to tell me its my throttle body spacer lol. We eventually got past that "confusion"

 

Dealership called last night and the mechanic "thinks" its being caused by either my PCV or Purge control solenoid valve... any suggestions?

 

Any updates on this?

 

It just got back from Acura. It was there for 4 1/2 weeks and they came back to me and said we can not see anything out of the ordinary. He pretty much flat out told me, we don't know whats wrong with it and we won't be able to fix it.

Now my transmission is making a shudder when in drive with the brakes applied. :/

 

could it just a mount, i.e. upper/side transmission mount?

 

It does not do it when the car is cold.. I have a bad upper transmission mount but it doesn't move or anything, and its been bad for like 2 years. I felt it with the car in drive and I couldnt feel the shuddering coming from it. I just posted a thread about it.

 

After reading through this thread I would just trade the car in and be done with the headache. I dont know how you have the patience for this.

 

For some reason I feel like this issue is related to a bad throttle body.

 

Replaced throttle body/map/tps all yesterday with a known good one. No change.

I read somewhere that over time the O2 sensors will become sluggish. Makes sense because the car doesnt rely on O2 readings until fully warmed up. I have 2 new primary O2s coming in today. After that, only 2 things left to replace are Coolant temp sensor, and fuel pump assembly and every sensor on the car will be replaced.

 

Bud, i feel so sorry for you.....it's time to bite the bullet.

 

I replaced the bank 1 primary O2, and unplugged the bank 2 one and there was no change. So the O2 are not the cause.

Literally the only things left to replace are Engine/Trans , and the fuel pump assembly.

Maybe I was just unlucky and its the fuel pump assembly and I just so happen to replace that last.

 

So today we tested volume of fuel and pressure of fuel and my volume of fuel is really low. The fuel that was actually getting to the rail had good pressure just was barely any. New fuel pump assembly going in tomorrow. Fingers crossed.

 

Anything new?

 

So interested to hear the latest. I would have given up long ago. I hope they figure this out. These cars seem to be super finicky. Im really not impressed. My Toyota Avalon never gave me any trouble. Im not impressed with Acura anymore. They are no where near the car Toyota makes.

 

Replaced the fuel pump with a OEM replacement and still no change at all. I am interested in why the mechanic said the "volume" of fuel was not good when he disconnected the line at the rail. When I disconnected at the pump, there was PLENTY of volume. My fuel covered trunk is evidence of that for sure. I am not sure where to go from here at all.. I dont really have anything else to replace except the fuel lines but i dont see them being intermittent like the problem is. Still no CEL at all. :/

The only things I can think of that havnt been replaced are :

Knock sensor
Cam /Crank sensor
Coils


Although what I noticed is that the problem will only start happening after I stop at a light or I turn the car off and start it back up. If I start the car in the morning, and jump on the interstate, it runs like a dream until I stop the car at a light or I turn it off and get back into it and drive away.

It is REALLY bad if the car is at operating temp, and I shut it off, turn it on, and start driving. It falls dead on its face when I do this. Isnt ever that bad regularly driving though.

 

You said that it runs fine when you get on the interstate. Does it continue to run fine even once at operating temp, or only for a short trip, and once you get off the interstate and get to a light, it starts to act up?

You said its bad if the car as at operating temp, and you turn it off, back on and start driving. Does it ALWAYS run poorly when up to temp, and always run well when cold?

If those hold true, it really sounds like something electronic that isn't liking the heat. It sounds like a dumb idea, but I would suggest ensuring that all of the plugs under hood and even under the dash are connected well. My friend had an explorer kick his butt for days that had a problem like this - every circuit independently would test good, but after running and driving for about 30 min it would run terrible. Ended up being a bad plug connection under the dash... Crazy things can happen.

 

This is GREAT input for me. I originally thuoght something electrical was acting up but after reading this whole thing I can say:

Problem will randomly happen at 9 out of 10 stop lights. But randomly at the 10th light, it will just take off like its right off the assembly line. The problem is so intermittent its crazy. The car runs PERFECT if I leave it overnight and its completely cooled down. If that's the case, it wont act up until at least 5/10 minutes of driving every time. I feel like the problem gets alot more tolerable if I get onto the interstate and keep a steady speed. This may be just because the acceleration at highway speeds is less load on the engine then lets say acceleration from a stop, or a slower speed. The entire sound of the engine/exhaust changes when it starts to act up pretty bad. It feels like im losing compression, and its all escaping if that makes any sense but im not losing oil and its not 100% of the time.

 

Get a salvaged Vsa modulator and replace it. I did that to mine and its done! Its been a while since i did it and didnt act up once.

Whatever you are describing here is as if you were talking about my car, i have to be the only other guy with the same exact issue.
Good luck !

 

I have unplugged the module many times, and even turned off VSA while driving with no change. The power loss doesnt feel anything like a VSA problem. The motor doesnt cut off, it completely bogs down like im suddenly towing a semi behind me.

 

Ok. You are still explaing a problem i used to have. But so be it, the modulator has the ability to reduce torque - thats a fact.

 

Ok. You are still explaing a problem i used to have. But so be it, the modulator has the ability to reduce torque - thats a fact. I bought one for 160 used, replaced and bled the brakes. The car pulls stronger and smoother in general. I dont think it ever felt as strong as it does now. Even new, i dont remember it this way. My gas milage is up quiet a bit as well, the idle is smoother then ever and i dont experience idle dips anymore. The exhaust note is not as loud when accelarting gradually.... Thats all after i replaced the modulator.

Sounds convincing to me ...

 

What happens if you were to go WOT from an interstate speed? Like put your foot down from say, 60 MPH? Does it intermittently happen then?

I would look into ways to test the knock sensor and fuel pressure regulator. This will sound stupid if the answer is yes, but you always put 91 in the car, correct?

Can you ever feel the cooling fans kick on?

 

If I put the pedal down at 60MPH you can still hear the crap sound from the engine like is struggling. Its not NEAR as quick as it normally is if it were running fine.

I just replaced the Fuel pump assembly which had the regulator in it to my knowledge.

I have always ran 93. I have not ever even put 91 in the car.

The knock sensor wasnt singled out for a test, but Acura had the car hooked up to a live-data scan for a few miles and I think knock-sensor was one of the live circuits they were monitoring.. I think it would have shown if it were bad?? I am not too sure..

If I get all my ducks in a row, Ill be in a 2013 Genesis 2.0T R-Spec in the next few weeks. I can't deal with this problem anymore.

 

i would also suggest replacing knock sensor, 02 sensors and vsa modulator before you decide to totally give up.

 

All 4 oxygen sensors have been replaced already. I have not replaced the knock sensor or the VSA module yet.. that is quite an expensive part from what I hear. I have unplugged the fuse related to it and nothing changed but a bunch of dash lights came on.

 

thats great


purchase a used VSA module from junkyard.. you just trying to see if it replicates same problem after swapping

hate to see you not replace 1 or 2 parts that could be culprit & waste all the invested time and money .. like BukvaMan said.. he experienced similar issue

 

I'm curious, how could it be the VSA modulator if it's been electrically isolated?

 

It is something heat related i'm leaning towards. For example, during the summer the problem was almost instantly after car warmed up. As the temperature has dropped, the problem is taking longer to present it self after starting and driving. The past 3 or 4 days its been in the high teens and low 20's and the problem didn't happen during my commute at all. But the car isnt overheating or anything. Coolant was flushed 2 months ago.

 

Mine was heat related also. But after changing the vsa modulator, even at cold it felt lighter and much stronger in general.

The hardest part is bleeding the brakes after changing the modulator. The modulator itself very easy...

 

Don't think engine temp but sensor or wiring temp. It really sounds like it could be a connection that gets weak after it gets warm. I'm just at a loss for what it could be that won't also give a CEL.