Engine RPM moves up and down
 

Please watch my video of whats going on. Its easier for me to make a video than to try and explain it, sorry. https://youtu.be/mUtdVvnlG8c

basically, when im constant on the throttle keeping the same position i can feel this happening. It's mostly in 4th and 5th gear between 1,000 and 2,000 rpm. Sometimes I think its from going up a slight grade but other times the road in perfectly flat. When it adjusts down (to where it should be) i can feel the car "kick" and can even hear the exhaust more. Its like the car is continuously connecting and disconnecting power. When it's low it feels and sounds great. But when it jumps up it just doesnt feel right. Also, i have a rip in the air intake boot that i covered up with tape.

Sorry for the long read. Im not looking for answers, i just want to read what some of you have to say. Btw im new to posting but I'm always on acurazine reading what everyone has to say. I love this forum.

Sorry i messes up actually linking the link.

perhaps the duct tape fix isnt a fix and is contributing to the vacuum leak you are experiencing?

I have the exact same issue, 03 TLS, 240K. Mine seems to do it, only from a cold start, through the first four or five miles of around town operation. The condition, is so SLIGHT, you probably wouldn't even notice it, unless, you were looking for it. The RPM fluctuation, is so slight, you can hardly feel it, yet, if you look at the Tack, it's definitely there. No vacuum leaks, all maintenance up to date, complete air induction system, thoroughly cleaned, etc., etc. I hate that it happens, but have become frustrated, trying to fix it!

Thank you for the input, i really appreciate it :smile: I probably will buy a new boot. I saw some on eBay for aroubd 20 bucks. I assume they are cheaply made from china. Would one of these be good enough?

I think it may be the bad boot, bad gas, or even an exhaust leak maybe? Im trying to rule everything out before I think about it being a transmission issue.

When did it start happening for you? I'm pretty sure mine has only been happening recently. For me its pretty much all the time. Even when its been runing for a while and has heated up. If i give it more gas it will go away, or like I said if i get higher in the rpm range it stops.

typically idle air control valve (IACV)

Noticed it, shortly after purchasing the car, June, 2014, @ 196K. Performed, FULL, 200K maintenance update, including, R&R all fluids, TB/WP/TENS/PLUGS/VALVES, etc., after which, the condition persisted. I regret, cleaning the IACV, rather than replacing it, with new OEM, while I was in there. It's somewhat of a pain, to get to. Since, it's such a slight, almost imperceptible problem, I've decide to LIVE WITH IT, until, and IF, it becomes noticeably worse! In the last 44K of operation, the symptom, hasn't changed.

CURIOUS to know, try locking it into 4th gear, and see if it goes away.

Should i use d4 for that or the sport shift? I will give it a try

Thanks for the suggestion, ill investigate this further

Ive been living with also. My car has 275k miles so i dont want to put in unnecessary money into it if i dont have to. I bought mine at 203k. And a few weeka later I had a blinking check engine light for misfire. That was when i replaced the plugs and coils. Other than that i havent changed anything else like transmission fluids or any other 200k maintenance. I will for 300k if she makes it. I dont wqbt to jynx but im sure we will

Alright so in d4 the 4th gear behave very different than 4th gear on d5, which seems weird to me. Its higher by about 250rpm. In d5 going 30 is 1250rpm but on d4 30 is 1500. And When I get off the gas it drops almost to idle and then sits at 1,000. Alsoif i give it a good amount of gas it will go to 2,500 but doesn't shift to 3rd.

In sport shift 4th gear it still fluctuates. But now im curious as to why d4 behaves so diferent than 4th gear in d5. Very weird. It seems like the torque converter or stall speed is more active. In d5 it locks, if that makes sense? I dont really understand TC and stall speeds so i may just be talking out my ass. In fact im fairly confident that i am.

Correct. In D4, torque converter lockup(overdrive) is disabled.

Okay cool. I dont really like it though. Why is it like that? would it be better on gas?

One thing i do like is i can go from 25 to 50mph at a constabt 2,000rpm. I think it looks cool to see the speedometer move but not the tac. Other than that i dont like it. I just use d5 or sport shift.

No, driving in 4th gear, will cause your car to use more fuel, because it's operating at a HIGHER RPM. As Iggy said, ( " Correct. In D4, torque converter lockup(overdrive) is disabled. " ) When I suggested 4th gear, I should have clarified, , to do so momentarily, just to determine, if the RPM fluctuation, remains, while in 4th, or, goes away, while operating in 4th. No need to use Sport Mode, just pull the gear selector lever down, into fourth.

Okay, that makes sense. To answer your question it does not happen in d4. I drove around almost all day yesterday in d4 for about 25 miles (city) and it didnt happen at all.

Mine does the same. I'm not sure, exactly, what this means. I wouldn't think, the torque converter operation, is relevant, in the speed range, where this issue is exhibited!. Out of curiosity, I'm going to try and locate an OEM throttle body, that appears to have been replaced, and see if it fixes the problem. As I mentioned in an earlier post, I wish I would have replaced my original IACV, instead of just cleaning it. It's such a pain to get to. I will also look into How, and Why, the IACV does what it does. The electronic controller, attached to the IACV, may play a part in this issue as well!

Did u ever get to replacing the IACV? I'm wondering if it helped you. I replaced my air filter and the intake boot that had a rip. It's much better but still does it over hills.

i messed around driving in D4 and D3 a lot and it doesnt happen at all. Not even going up hills. Same roads, same speed, same gear. Why is that? Do you think this means the TQ lock up is failing?

( " Did u ever get to replacing the IACV? I'm wondering if it helped you. I replaced my air filter and the intake boot that had a rip. It's much better but still does it over hills." ) Haven't stumbled across recently replaced OEM IACV yet. still looking