1992 LS400 driving issues
#1
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1992 LS400 driving issues
I know this post has been talked about countless times. I just want a little more recent info/news/fixes.
92ls400
check engine light on intermittently code 25 only. Engine lean malfunction.
and the car has a very bad misfire almost undrivable. Heavy throttle misfires like a mffffff. Light throttle feels ok(sometimes) On idle it burps here and there.
I don’t want to keep throwing money at it. I was going to buy ignition coils and dizzy caps and rotors. But I’m not sure if it could be a sensor failing/failed. Please help. I want my baby girl healthy
replaced:
spark plugs and wires.
All coolant temp sensors.
tps sensor.
idle air control valve.
Deleted egr.
92ls400
check engine light on intermittently code 25 only. Engine lean malfunction.
and the car has a very bad misfire almost undrivable. Heavy throttle misfires like a mffffff. Light throttle feels ok(sometimes) On idle it burps here and there.
I don’t want to keep throwing money at it. I was going to buy ignition coils and dizzy caps and rotors. But I’m not sure if it could be a sensor failing/failed. Please help. I want my baby girl healthy
replaced:
spark plugs and wires.
All coolant temp sensors.
tps sensor.
idle air control valve.
Deleted egr.
#2
I would confirm that the engine is getting adequate fuel supply:
- Fuel pump providing adequate pressure/volume.
- Injectors unplugged.
- Fuel filter unplugged.
- Fuel pump pickup filter unplugged.
- What did the business end of the old plugs look like?
#3
Moderator
In case the code is only 25, it simply means that the problem is only one side of the bank. I'd rather think it's a vacuum leak, clogged injectors or a failing OXL1 of bank 1. To check the leak, a smoke machine is useful to find out the exact leaking point. The OXL1 can be checked as is explained here.
If you have the code 26 too, I will add to check the fundamental fuel supply issues.
If you have the code 26 too, I will add to check the fundamental fuel supply issues.
Last edited by Yamae; 05-31-23 at 05:40 PM. Reason: typo issue
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CELSI0R (05-30-23)
#4
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I would confirm that the engine is getting adequate fuel supply:
- Fuel pump providing adequate pressure/volume.
- Injectors unplugged.
- Fuel filter unplugged.
- Fuel pump pickup filter unplugged.
- What did the business end of the old plugs look like?
#5
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In case the code is only 25, it simply means that the problem is only one side of the bank. I'd rather think it's a vacuum leak, clogged injectors or a failing OXL1 of bank 1. To check the leak, a smoke machine is useful to find out the exact leaking point. The OXL1 can be checked as is explained here. https://www.youtube.com/watch?v=VNJXLS_SDUI
If you have the code 26 too, I will add to check the fundamental fuel supply issues.
If you have the code 26 too, I will add to check the fundamental fuel supply issues.
I’ve smoked the intake before and found a leak behind the intake manifold. Assumed it was intake gaskets. Replaced them.
Smoked again and still a leak. Ended up being a leak from the vacuum line to the back of the manifold from brake booster. replaced that.
smoked again and has no leaks. This was about a year ago. And it was running fine until about 2 weeks ago.
I replaced my upstream o2 sensors and I still have the same issue…. Idk what to do
#7
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I would confirm that the engine is getting adequate fuel supply:
- Fuel pump providing adequate pressure/volume.
- Injectors unplugged.
- Fuel filter unplugged.
- Fuel pump pickup filter unplugged.
- What did the business end of the old plugs look like?
forgot to mention I have new fuel pump and filter
Trending Topics
#8
Has the ECU been repaired? Any further diagnosis is impossible until the ECU is confirmed healthy.
How to test if you don't know if it's been repaired:
https://www.clublexus.com/forums/ls-...-by-yamae.html
https://www.clublexus.com/forums/ls-...capacitor.html
How to test if you don't know if it's been repaired:
https://www.clublexus.com/forums/ls-...-by-yamae.html
https://www.clublexus.com/forums/ls-...capacitor.html
#9
I know this post has been talked about countless times. I just want a little more recent info/news/fixes.
92ls400
check engine light on intermittently code 25 only. Engine lean malfunction.
and the car has a very bad misfire almost undrivable. Heavy throttle misfires like a mffffff. Light throttle feels ok(sometimes) On idle it burps here and there.
I don’t want to keep throwing money at it. I was going to buy ignition coils and dizzy caps and rotors. But I’m not sure if it could be a sensor failing/failed. Please help. I want my baby girl healthy
replaced:
spark plugs and wires.
All coolant temp sensors.
tps sensor.
idle air control valve.
Deleted egr.
92ls400
check engine light on intermittently code 25 only. Engine lean malfunction.
and the car has a very bad misfire almost undrivable. Heavy throttle misfires like a mffffff. Light throttle feels ok(sometimes) On idle it burps here and there.
I don’t want to keep throwing money at it. I was going to buy ignition coils and dizzy caps and rotors. But I’m not sure if it could be a sensor failing/failed. Please help. I want my baby girl healthy
replaced:
spark plugs and wires.
All coolant temp sensors.
tps sensor.
idle air control valve.
Deleted egr.
Had the same issue for a long time. Ended up to be a "working" coil breaking down. Idle fine and misfire on load and throttle. Take a timing light and clip on the coil wire. It needs to flash very fast, NOT SLOW AND INTERMITTENT. It causes enough spark for idle but breaks down on rev or load.
#10
I know this post has been talked about countless times. I just want a little more recent info/news/fixes.
92ls400
check engine light on intermittently code 25 only. Engine lean malfunction.
and the car has a very bad misfire almost undrivable. Heavy throttle misfires like a mffffff. Light throttle feels ok(sometimes) On idle it burps here and there.
I don’t want to keep throwing money at it. I was going to buy ignition coils and dizzy caps and rotors. But I’m not sure if it could be a sensor failing/failed. Please help. I want my baby girl healthy
replaced:
spark plugs and wires.
All coolant temp sensors.
tps sensor.
idle air control valve.
Deleted egr.
92ls400
check engine light on intermittently code 25 only. Engine lean malfunction.
and the car has a very bad misfire almost undrivable. Heavy throttle misfires like a mffffff. Light throttle feels ok(sometimes) On idle it burps here and there.
I don’t want to keep throwing money at it. I was going to buy ignition coils and dizzy caps and rotors. But I’m not sure if it could be a sensor failing/failed. Please help. I want my baby girl healthy
replaced:
spark plugs and wires.
All coolant temp sensors.
tps sensor.
idle air control valve.
Deleted egr.
#11
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Join Date: May 2023
Location: virginia
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Figured the issue out about a week ago. Passenger side ignition coil (USDM) is the culprit (Both are new now).
Threw some coils on and car misfire was gone right away.
I still have a lean malfunction code (unrelated issue). But misfire is completely gone.
Never assume something is ok just because it hasn’t completely failed.
fuel injectors are probably my issue as since I changed the failed fuel filter that was broken inside :/ 🤞🏼🤞🏼🤞🏼 Injectors on this car aren’t an enjoyable or easy job
Threw some coils on and car misfire was gone right away.
I still have a lean malfunction code (unrelated issue). But misfire is completely gone.
Never assume something is ok just because it hasn’t completely failed.
fuel injectors are probably my issue as since I changed the failed fuel filter that was broken inside :/ 🤞🏼🤞🏼🤞🏼 Injectors on this car aren’t an enjoyable or easy job
#12
Intermediate
Figured the issue out about a week ago. Passenger side ignition coil (USDM) is the culprit (Both are new now).
Threw some coils on and car misfire was gone right away.
I still have a lean malfunction code (unrelated issue). But misfire is completely gone.
Never assume something is ok just because it hasn’t completely failed.
fuel injectors are probably my issue as since I changed the failed fuel filter that was broken inside :/ 🤞🏼🤞🏼🤞🏼 Injectors on this car aren’t an enjoyable or easy job
Threw some coils on and car misfire was gone right away.
I still have a lean malfunction code (unrelated issue). But misfire is completely gone.
Never assume something is ok just because it hasn’t completely failed.
fuel injectors are probably my issue as since I changed the failed fuel filter that was broken inside :/ 🤞🏼🤞🏼🤞🏼 Injectors on this car aren’t an enjoyable or easy job
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