Rough idle + others
03-30-2019, 11:26 PM
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Rough idle + others
Sorry this is my first post but I'm coming toward the end of my rope at this point.
I've lurked for a long time and searched for my issues but can only find things here and there. I'll summarize my problems but have no idea what are related to each other:
125k 2005 Z
Rough idle that bounces from 700-400 RPM recently
Replaced spark plugs but found oil in the 6 (? Closest to wall, driver side)
Cleaned after market air filter
Replaced PCV valve
Cleaned MAF sensor
Oil change
Coolant flush
I popped a random misfire code after it wouldn't turn over POST spark plug change, and then I just now hit P0171 lean error code after all the above was done.
At this point I'm assuming the valve cover needs to be replaced because of the oil but not sure it caused the errors. Also the sound of the engine at idle was **** a couple months before the RPMs started bouncing, so not sure if that's related either.
OBDII sensor reads green for everything, at the moment.
Fuel pump? Injectors? Coil packs? Valve cover? All the above?
I've lurked for a long time and searched for my issues but can only find things here and there. I'll summarize my problems but have no idea what are related to each other:
125k 2005 Z
Rough idle that bounces from 700-400 RPM recently
Replaced spark plugs but found oil in the 6 (? Closest to wall, driver side)
Cleaned after market air filter
Replaced PCV valve
Cleaned MAF sensor
Oil change
Coolant flush
I popped a random misfire code after it wouldn't turn over POST spark plug change, and then I just now hit P0171 lean error code after all the above was done.
At this point I'm assuming the valve cover needs to be replaced because of the oil but not sure it caused the errors. Also the sound of the engine at idle was **** a couple months before the RPMs started bouncing, so not sure if that's related either.
OBDII sensor reads green for everything, at the moment.
Fuel pump? Injectors? Coil packs? Valve cover? All the above?
03-31-2019, 12:15 PM
#2
Well you will eventually want to replace that valve cover where you found oil in the spark plug well, because the built-in seal is no longer working, but I do not think this is your current issue, and is not an immediate concern.
A random misfire code is likely not the coil-packs failing either, as if it were, you should get a code relating to that specific cylinder/ coil. Ensure that you've plugged the coil-packs in with their correct plug, as I've heard of some people mixing up some of the plugs. If I remember correctly, my car had a P0171 code and it turned out to be a failing catalytic converter, as well as a primary O2 sensors (on the headers). I'm not sure about the DE engines, but on the later models you could check if the O2 sensor was functioning by the voltage read-out from a OBD2 scanner, and some kind of diagnostic app with live data, (I use Torque).
However, I'm not positive if these above things would cause the rough idle. Start with these relearn procedures in post #2 in order, in this thread: Idle air relearn.
I've had idle issues such as yours after taking apart the throttle bodies/ manifold, but after performing the relearn it went back to normal.
A random misfire code is likely not the coil-packs failing either, as if it were, you should get a code relating to that specific cylinder/ coil. Ensure that you've plugged the coil-packs in with their correct plug, as I've heard of some people mixing up some of the plugs. If I remember correctly, my car had a P0171 code and it turned out to be a failing catalytic converter, as well as a primary O2 sensors (on the headers). I'm not sure about the DE engines, but on the later models you could check if the O2 sensor was functioning by the voltage read-out from a OBD2 scanner, and some kind of diagnostic app with live data, (I use Torque).
However, I'm not positive if these above things would cause the rough idle. Start with these relearn procedures in post #2 in order, in this thread: Idle air relearn.
I've had idle issues such as yours after taking apart the throttle bodies/ manifold, but after performing the relearn it went back to normal.
03-31-2019, 05:25 PM
#3
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Well you will eventually want to replace that valve cover where you found oil in the spark plug well, because the built-in seal is no longer working, but I do not think this is your current issue, and is not an immediate concern.
A random misfire code is likely not the coil-packs failing either, as if it were, you should get a code relating to that specific cylinder/ coil. Ensure that you've plugged the coil-packs in with their correct plug, as I've heard of some people mixing up some of the plugs. If I remember correctly, my car had a P0171 code and it turned out to be a failing catalytic converter, as well as a primary O2 sensors (on the headers). I'm not sure about the DE engines, but on the later models you could check if the O2 sensor was functioning by the voltage read-out from a OBD2 scanner, and some kind of diagnostic app with live data, (I use Torque).
However, I'm not positive if these above things would cause the rough idle. Start with these relearn procedures in post #2 in order, in this thread: Idle air relearn.
I've had idle issues such as yours after taking apart the throttle bodies/ manifold, but after performing the relearn it went back to normal.
A random misfire code is likely not the coil-packs failing either, as if it were, you should get a code relating to that specific cylinder/ coil. Ensure that you've plugged the coil-packs in with their correct plug, as I've heard of some people mixing up some of the plugs. If I remember correctly, my car had a P0171 code and it turned out to be a failing catalytic converter, as well as a primary O2 sensors (on the headers). I'm not sure about the DE engines, but on the later models you could check if the O2 sensor was functioning by the voltage read-out from a OBD2 scanner, and some kind of diagnostic app with live data, (I use Torque).
However, I'm not positive if these above things would cause the rough idle. Start with these relearn procedures in post #2 in order, in this thread: Idle air relearn.
I've had idle issues such as yours after taking apart the throttle bodies/ manifold, but after performing the relearn it went back to normal.
I've done the idle relearn a few times (after MAF clean, after filter clean, and after spark plugs) and it doesn't seem to help. Well that's not entirely true... After I cleaned my intake the car was running like garbage because I forgot to do the relearn and after I did, it ran great (aside from the idle issue).
You're one of many that have suggested the O2 sensor and I'm beginning to think that's the culprit. Or my cats. Theres a weird sound I can hear inside my car but NOT when my head is in the engine, and I'm thinking it has something to do with my exhaust system. The sound seems like it's under the dash on the passenger side. Perhaps it's related to the cat? I haven't been under my car in a while, maybe that's the next step.
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