Hey guys,

Just got my car back from the shop & replaced valve cover and upper plenum gaskets, plugs, pcv, and had intake path cleaned. Car now idles rough when stopped, but only when the transmission is engaged. Engine stutters and RPMs jump in response to stuttering (between 800-650 RPM). This goes away when placed in Park or Neutral, does anyone have any suggestion or experienced this before? Thanks.

 

was the Idle Air Control Valve cleaned?

 

The IACV was cleaned as well, maybe a replacement is necessary. I just find it hard to believe that it wouldn't idle roughly all of the time.

 

Likely it does, but when in gear the load on the engine makes it much more noticeable.

 

I am going to try cleaning it again and then see what the result is, but could there be any other culprit? Does a bad coil pack demonstrate similar behavior? Thanks for the replies.

 

OK, doing a search outside of the ORG, I found that others experiencing this issue after cleaning the IACV replaced the Throttle Position Sensor (TPS) to solve this problem. Anyone already replaced their TPS? Thanks.

 

Just following up, but has anyone replaced their TPS and what were the results? I am still experiencing a rough idle after cleaning the IACV. The TPS is ordered but I am awaiting delivery. Thanks.

 

Yo turbolaw99, I'm having the exact same problems as you. My car revs at about 700-900 in park/neutral, but only at about 550 and sometimes lower when in gear. It feels like there's a slight chugging at low speeds, but nothing noticeable at higher speeds. I've been told that the TPS is to blame, so I'm thinking about swapping that out. Can you tell me if the TPS fix worked for you? It would really help me out.

 

Sounds like what my Maxima did when it had a bad coil pack. I strongly suggest that you check those. This could save you a lot of fustration in the future.

 

I've been trying to hunt down the exact problem that shorterchild has described. I've changed all the items that would have anything to do with this problem. That includes IACV/TB cleaning with fresh gaskets, injector cleaning, and swapped coils that came from a maxi with 50k miles. The ONLY thing that hasn't been changed is the TPS, but i'm afraid to touch it because the bolts that hold it are stripped & rusted.

 

don't forget the small stuff like the pcv "valve". I have a feeling that's what the culprit is.

 

My car has a bit of a rough idle in D, 2 and 1. It "feels" like the torque converter is engaging too early as its highly eager to get off the line with no acceleration. It idles nicely at ~750 rpm but when it revs, its smooth as.

I checked all my coil packs - all of them were fine. IACV is fine. TPS has been replaced.

I suspect engine mounts are worn and its just excess vibration.

 

Thanks for the tip, AndrewR. But, i replaced that too. I did everything in the sticky's (and then some).

Jordanalley might be right about the motor mounts. Especially me being a GLE with that electronic front engine mount.

 

Did you received any Code??? Is there any misfired on any of the engine?
1. Make sure the ignition is good. Swap between the two engines to make sure it is not a ignition coil.
2. If it is indeed not a ignition coil, then just unplug the ignition coil which you suspect as a misfired and listen very careful to hear any different with plug and unplug the suspected misfired engine.
3. If it is indeed a different, it might be the fuel injector. NOTE: Please please buy a remanfacture "NOT SALVAGE" from ebay...or junk yard.
4. Good Luck....follow the instruction at YOUR OWN RISK.

 

did you really just bump a 3 year old thread?

 

I took my 1995 Nissan maxima in fir a smog today and they couldn't do the "Dino" test because when in drive the idle bounces. Any suggestions?

 

When I took my 1995 Nissan maxima in for smog today they couldn't give my car a "Dino" test because the idle bounced in drive and they couldn't get a reading. Any suggestions?

 

I'm bumping this because I have the same problem. No other suggestions or results?

 

check your map/baro solenoid valve and make sure there isnt any pinched connections going to or from it. had same problem turned out to be a pinched vacuum line attached from it, hope that helps, good luck!