Rough idle & dies when engage clutch??

[bszopi]

Reposted to the forum for velasaa2522

Hi still kinda new to the form. I'm have some trouble with my lq1. Here's what happens, the car runs great on a cold start. But once it warms up to the proper running temp is when the problems start. When at a stop it has a slight misfire. Then when I'm driving I'll engage the clutch to come to a stop and it will have rough idle and die. Not too sure what it could be. It has a brand new idle air control valve & fuel filter... tune up maybe?

[pocket-rocket]

I would start with a tune up, including a new O2 sensor, and then go from there.

[55trucker]

It's not easy trying to do an *armchair* diagnosis. It could be one item or a few small problems compounding this.
You really need to get a scanner on the engine & do a realtime scan to see what the display tells you, what codes are presently there, remove them and drive the car again in realtime to see if any reset themselves. Once you've eliminated any possible *emission* related sensor problems, then you can start investigating either mechanical or electrical over mechanical faults.
This may not be want you want to hear but you don't want to throw money at a problem going from A to B to C etc etc until you hit on the problem.

[pocket-rocket]

It's not easy trying to do an *armchair* diagnosis. It could be one item or a few small problems compounding this.
You really need to get a scanner on the engine & do a realtime scan to see what the display tells you, what codes are presently there, remove them and drive the car again in realtime to see if any reset themselves. Once you've eliminated any possible *emission* related sensor problems, then you can start investigating either mechanical or electrical over mechanical faults.
This may not be want you want to hear but you don't want to throw money at a problem going from A to B to C etc etc until you hit on the problem.

No, but 9 times out of 10, questions like this start without decent wear parts because of maintenance neglect, which is why I tend to ask/suggest tuneup, including the O2, because otherwise it gets changed about as much as a cabin filter.

[TGP37]

I agree with P Rocket, and here is why. But first, to test this idea, simply unplug the O2 sensor. That will force OL mode, or deny CL when warming up, same thing.

When the symptoms appear when the car is warm, it indicates an OL-CL issue. The O2 sensor becomes a major suspect as that is the one major component in transition from OL to CL.

O2's tend to fail on the rich side. Well, they read false lean readings and pulls the LTFT's towards a richer AFR. At first this is okay and in fact, the car will have MORE power and a smoother idle at first. So the problem goes unoticed, most people dont think the O2 is dying when the car is running better then normal.

But after some time the fueling gets extreme and causes idle problems, especially after moderate to heavy throttle.

The idle gets rough suddenly when it reaches a little below operating temp. When the car goes WOT, the O2 is not used and the LTFT's basically return to normal for the WOT duration (PE Mode). But when the throttle returns to 0, but the RPMS are higher, a ton of fuel gets dumped and causes the problem to worsen. Especially when enleanment is vital for smooth return to idle or low throttle.

The idle rpm will hunt up/down, sputter and potentially stall.

The car runs fine at 50% or more throttle.