Rough idle - comes and goes
#19
Registered Member
First thing I thought was dirty throttle bodies... I clean them once a year... I had cleaned them at the beginning of this year and then again a few days ago along with the maf sensor when this started occurring thinking that may resolve the issue... They weren't even really dirty but still cleaned them. That didn't fix the problem. Also did the reprogramming after cleaning TB to see that may fix the issue... still nothing.
#21
Registered Member
Thread Starter
@slartibartfast,
If the the issue STREETTEC is experiencing is similar to mine, what I experienced was a momentary stall or significant miss when stopped in drive (+/- 650 rpm). For instance, sitting at a stop light the car felt like it died for a moment, however it was short lived and recovered immediately. It may do this twice in the same day or not for a week - there didn't seem to be any rhyme or reason to it and I haven't noticed it since last fall.
I am curious as to the stalling you mentioned and I may move that to another thread. Since I purchased this car I've noticed that under full acceleration from stop there is a hesitation that is often accompanied by what sounds like pre-detonation (i.e. sounds like a diesel). I never hear the sound once the car is moving so I don't think it's something like worn main bearings and I have cleaned the throttle bodies with a relearn that didn't help. I may clean them again and perform the relearn sequence - now that I've found some good resources (DIYMotivate and others) I need to ensure I'm performing all steps correctly.
-Eric
If the the issue STREETTEC is experiencing is similar to mine, what I experienced was a momentary stall or significant miss when stopped in drive (+/- 650 rpm). For instance, sitting at a stop light the car felt like it died for a moment, however it was short lived and recovered immediately. It may do this twice in the same day or not for a week - there didn't seem to be any rhyme or reason to it and I haven't noticed it since last fall.
I am curious as to the stalling you mentioned and I may move that to another thread. Since I purchased this car I've noticed that under full acceleration from stop there is a hesitation that is often accompanied by what sounds like pre-detonation (i.e. sounds like a diesel). I never hear the sound once the car is moving so I don't think it's something like worn main bearings and I have cleaned the throttle bodies with a relearn that didn't help. I may clean them again and perform the relearn sequence - now that I've found some good resources (DIYMotivate and others) I need to ensure I'm performing all steps correctly.
-Eric
Last edited by llebcire; 08-04-2018 at 10:33 AM.
#22
Super Moderator
iTrader: (7)
Dirty throttle bodies cause a momentary hesitation when taking off from a stop. Of course, there can be other causes, like the afore mentioned vacuum leak.The transmission is the culprit if you want a downshift and don't get it. Those are two primary causes of driveability issues.
#23
Registered Member
@slartibartfast,
If the the issue STREETTEC is experiencing is similar to mine, what I experienced was a momentary stall or significant miss when stopped in drive (+/- 650 rpm). For instance, sitting at a stop light the car felt like it died for a moment, however it was short lived and recovered immediately. It may do this twice in the same day or not for a week - there didn't seem to be any rhyme or reason to it and I haven't noticed it since last fall.
-Eric
If the the issue STREETTEC is experiencing is similar to mine, what I experienced was a momentary stall or significant miss when stopped in drive (+/- 650 rpm). For instance, sitting at a stop light the car felt like it died for a moment, however it was short lived and recovered immediately. It may do this twice in the same day or not for a week - there didn't seem to be any rhyme or reason to it and I haven't noticed it since last fall.
-Eric
@slartibartfast - Yeah, I am thinking either vacuum leak or bad coil pack
I also noticed yesterday when trying to accelerate on the interstate to pass someone it was really lagging. It took awhile to get from 30mph to 60mph.
Going to do some more troubleshooting and see what I can figure out. If you guys have anymore ideas on a solution keep them coming, they are more than welcomed! I know with the symptoms it can be a multitude of things that maybe causing the issue.
Going to check for a vacuum leak and then check the coil packs...
#24
Registered Member
So I finally got a error message code!! I was actually excited when I got it!! So it could help answer what problems the G was having. The error message I got was "P0303 - Powertrain Cylinder 3 Misfire Detected"
So I switched coil pack 3 with coil pack 5 and ran her again and got the message that it was now cylinder 5!! Replace the coil pack with a new and she is running great now!!
Thank you to the ones that helped trying to troubleshoot! Appreciate it! Hope this helps others!!
So I switched coil pack 3 with coil pack 5 and ran her again and got the message that it was now cylinder 5!! Replace the coil pack with a new and she is running great now!!
Thank you to the ones that helped trying to troubleshoot! Appreciate it! Hope this helps others!!
The following 2 users liked this post by STREETTEC:
llebcire (08-12-2018),
slartibartfast (08-11-2018)
#25
Registered Member
Thread Starter
-Eric
#26
Registered Member
Thread Starter
Update - I'm not sure it's corrected.
I might have stopped paying attention as when I purchased the car I thought that a Japanese luxury car over $40k should have a smooth idle after owning Honda, Acura, Toyota and Lexus products. Looks like it's still around 500 in drive (+/- 650 in neutral/park) and paying attention last night it wasn't perfectly smooth.
-Eric
I might have stopped paying attention as when I purchased the car I thought that a Japanese luxury car over $40k should have a smooth idle after owning Honda, Acura, Toyota and Lexus products. Looks like it's still around 500 in drive (+/- 650 in neutral/park) and paying attention last night it wasn't perfectly smooth.
-Eric
#27
Registered Member
iTrader: (1)
So is the car still stumbling? If not then I believe this is a non issue. As mentioned earlier, the car will idle at different RPMs depending on the gear selected.
Maybe just sell it since you keep mentioning other brands with smoother idles.
Maybe just sell it since you keep mentioning other brands with smoother idles.
#28
Registered Member
Thread Starter
I love the car - just expected better refinement whereas the G37 is more adrenaline with luxurious touches. I can't get the reliability/repair costs in a German car or the performance in Lexus (for the same price) so every car option has strengths and weaknesses.
It doesn't stumble which I attribute to cleaning the TBs (have a thread here - they were filthy) and idle re-learn. The idle isn't "that" rough, no one ever says anything, just not as smooth as I expected, however the car did have 66K on it when I bought it and I'm the third owner so I don't know how it was driven/treated previously. Looking at the Carfax 1st owner drove a lot and 2nd owner barely at all.
I did notice the other day that after I drive with more of a spirited nature, in DS, the car idles smoothly at 650 in drive. Actually, after driving spiritedly the car acts different, especially in the way the transmission reacts/shifts.
-Eric