Lexus RX P if your catalytic convertor fails completely, you eventually won't be able to keep the car running. Your gas mileage will also be terrible, so you should try and fix it as soon as you can. So you should chech it on our car models.
Disconnected, dirty or fouled spark plugs are common causes for engines that won't start. Spark plugs typically need to be replaced every season or 25 hours of use. You should also check that the spark plug gap is set properly.
If your spark plugs look good, problems with your ignition system can also preventing a spark. These can range from a faulty spark plug lead, shorted kill switch or flywheel key damage.
Parts or components should not be replaced with reference to only a P DTC.
P0304 LEXUS - Cylinder 4 Misfire Detected
The vehicle service manual should be consulted for more information on possible causes of the fault, along with required testing. Code Search Please fill the "Code Box" to find engine fault code. Ways to read engine trouble codes. Ways to clear check engine light on car panel.
Check Engine Light Dictionary Ways to clear check engine light on car panel. Main engine trouble code archive on Web. Copyright EngineTroubleCode. Check engine light comes on Engine stalling or misfiring Engine performance issues Car not starting.
If one of these reasons for P code is occuring now you should check P repair processes.
Now don't ask yourself; What should you do with P code? The solution is here :.Commonly associated with codes: P P indicates that cylinder number 4 is experiencing misfires. A misfire occurs when an insufficient amount of fuel is burning in a cylinder. The efficient burning of fuel is essential to engine operation as the combustion of fuel is what provides the energy to power the engine.
A misfire from one or more cylinders can be caused by many reasons from a faulty ignition system, fuel system, or internal engine failure. When P occurs, it should be fixed immediately as long term driving with engine misfires could cause consequential damage to your engine.
Many times, P occurs when there are worn out spark plugs, spark plug wires, or a faulty ignition coil. P should be repaired immediately. Loose fitting electrical connectors and broken or disconnected vacuum hoses are often overlooked. For error code P, one or more of the below repairs may be needed to solve the underlying issue. For each possible repair, the estimated cost of repair includes the cost of the relevant parts and the cost of labor required to make the repair.
Changed plugs and wires and still have a misfire at idle, only at idle. Runs perfect at normal highway speeds.
P0304 Lexus Cylinder 4 Misfire Detected
What is going on, please help. Thanks for all the good info. Some of the older models had issues with water getting past the cowl seal between the windshield and hood. Usually that got in to the 4 plug well and caused issues, but it could run elsewhere along the top of the engine. I blew out the water with air and it solved all the issues.
Better than average, 1st to suggest a cam or crank sensor, although my problem comes and goes and is lessened by using octane booster. I have swapped plug and coil packs with another cyl, still throws a p When it runs good, it runs great, and Will as soon as you clear the code, then when your light comes on, it is very sluggish.
I would think maybe cam timing actuators, but they have been replaced, and it runs too good when it does to suspect an exhaust restriction, leaking valve or vacuum leak. Maybe I will swap fuel injectors next.
Coil packs OK spark plugs ok Ecu ok Has been to the garage for two weeks. On older cars with 80k or more miles where I bought cheap gas, this code was caused by the spray pattern on the fuel injectors. I bought 32oz bottles of fuel injector cleaner and that got me 15k more miles down the road and the engine light turned off by itself. When it came back on a couple years later, I had the Toyota dealer test the injectors and they validated two were bad. Then I took to a local mechanic who replaced them for half price of the dealer.
Mine is a Seat Leon 2. It happens only over 80degrees engine temp.CARspec now offers walnut shell blasting of the intake valves to help prevent this issue! The idle can often cause the car to stall and the check engine light to flash, but is intermittent in nature and can fool even the most seasoned auto mechanic. So what the story here with the problem and what should an owner do? The problem lay in the design of the engine, specifically the shortcomings of the direct injection system.
Because the fuel injectors have been moved from the intake tract leading into the engine upstream of the intake valves into the combustion chamber, the fuel mixture no longer cleans the intake valves of harmful carbon deposits. While moving the injectors into the combustion chamber improved fuel economy and power, the lack of cleaning leads to buildup.
This buildup eventually breaks off and is ingested into the engine causing the intake and exhaust valve to hang open causing a partial misfire or damage to pistons, rings and cylinder walls. IS and GS direct injection engines benefit heavily from regular induction services to help dissolve these intake valve deposits. You can read more about that process here. Regular oil changes and the occasionally going full throttle where safe has also helped owners prevent the condition.
How can you tell if you have the issue? Before you take your vehicle to your local Lexus mechanic, try duplicating the concern by:. Fortunately for owners Lexus extended the warranty for this specific issue, to 9 years with no mileage limit as part of campaign ZLA. They will repair your Lexus with either new pistons and rings IS or by cleaning the pistons and replacing the rings GS For those unfortunate enough to have the condition and are out of warranty, CARspec offers an alternative repair for owner not willing to rebuild their engine without first exhausting all options — a top engine clean of the pistons, rings and intake valves in conjunction with an induction service.
Following Lexus repair bulletin L-SB, the intake manifold is removed, the cylinders filled with a small amount of special GM top engine cleaning product, and the cylinders allowed to soak before the engine is reassembled and test driven. This can smooth over the misfire and rough run concerns of owners.
I was driving my car after i got my oil change. I started having issues. My car started stalling and my raido went out then it wouldny drive. They did top engine clean next day engine light came on again.
What do you think I should do next? What can I do. Your best bet is to approach Lexus with the concern first. If they made a previous repair attempt ie. If not, a local Lexus specialist can give you some options on repairing the cause of the misfire if it is caused by carbon buildup.
Great post! This is good news for all of us who have suffered through this engine design defect! At 82k miles, I finally took it into Lexus and they covered the engine cleaning and replaced a couple pistons and rings. I recently took the car in for another recall with k miles on itand while they had the manifold off, the Lexus tech showed me that the carbon build up was already coming back and that it would eventually cause the same misfires.
How much does your service cost? The service take about an hour. For more severe misfires, CARspec recommends a carbon cleaning of the piston rings and pistons using a top engine clean product combined with a more intense intake valve cleaning manually removing the carbon. Thanks for the quick reply.
The Recall nightmare! I purchased a used 06 is November of I notice a gas odor, what timing! A bit concerned so I call lexus dealer they fix the sensor recall they did an inspection stating everything passed. I got home later that day I still can smell gas.However, an oxygen sensor is easy to replace on many cars and is usually detailed in the owner's manual. If you know where the sensor is, you only have to unclip the old sensor and replace it with a new one.
Regardless of how you approach it, you should get this fixed right away. So you should chech it on our car models. Disconnected, dirty or fouled spark plugs are common causes for engines that won't start. Spark plugs typically need to be replaced every season or 25 hours of use. You should also check that the spark plug gap is set properly. If your spark plugs look good, problems with your ignition system can also preventing a spark. These can range from a faulty spark plug lead, shorted kill switch or flywheel key damage.
Parts or components should not be replaced with reference to only a P DTC. The vehicle service manual should be consulted for more information on possible causes of the fault, along with required testing. Code Search Please fill the "Code Box" to find engine fault code.
Ways to read engine trouble codes. Ways to clear check engine light on car panel. Check Engine Light Dictionary Ways to clear check engine light on car panel. Main engine trouble code archive on Web. Copyright EngineTroubleCode. Check engine light comes on Engine stalling or misfiring Engine performance issues Car not starting.
If one of these reasons for P code is occuring now you should check P repair processes. Now don't ask yourself; What should you do with P code? The solution is here :.P is a relatively common trouble code with any vehicle, that includes the Lexus IS P is certainly a cause for concern, and should be considered a threat to the drivability your IS It will often be accompanied by codes P, PPetc….
Fixing P should be considered a high priority. The engine is also not firing all of the fuel, so raw fuel is also passing through Cylinder 4 into the exhaust. Mileage may suffer as well when your IS has P as well. P is a cylinder specific misfire code, which means that Cylinder 4 is misfiring and causing the code.
There are quite a few things that can cause the P trouble code to trigger the Lexus IS Here are the most common problems that will throw the code. They are presented somewhat in order from most to least likely to be causing the code:.
If you follow the items listed above you should be able to fix the P Inspect and test the parts of the ignition system around the cylinder to determine whether or not you need to replace the coil packs, plugs, or wires. Most of the time one of those three things will end up being the problem. You need to reset the trouble codes and swap the coil pack, wire, and plug from Cylinder 4 to another. After that, Go ahead and replace them or have them tested.
After that you would want to test the fuel injection system. P is cause for concern and left unfixed can leave you stranded or make the vehicle virtually un-drivable. Fixing the problem causing the code to fire can save you time and money and keep your Lexus IS from breaking down. Quick action may also save your catalytic converter from going bad. Good luck diagnosing the issue. If there is anything that you would like to add please leave a comment below. Lexus IS P Definition P is a cylinder specific misfire code, which means that Cylinder 4 is misfiring and causing the code.
The vehicle itself may begin to run rough. It depends on how serious the misfire is. The vehicle may produce excess vibration, especially at lower RPM. Fuel mileage may suffer. You may smell raw gas coming from the tail pipe. The vehicle may backfire. Take a look at the electrodes and see if they are in good shape.
Most vehicles now come with iridium plugs that need changed very infrequently.Start by checking the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins. Tech Notes What does this mean?
The auto repair labor rates vary widely across the country, and even within the same city. By monitoring variations in the crankshaft rotation speed for each cylinder, the ECM can detect individual cylinder misfire events. Extreme cylinder misfire events can cause catalytic converter damage. The malfunction indicator lamp MIL will flash when the conditions for catalytic converter damage are present.
When the ECM detects that one or more specific cylinders are misfiring, the DTC for the respective misfiring cylinder will set, and up to 2 of the corresponding fuel injectors are disabled for a minimum of 30 s. The ECM will then re-enable the fuel injector and, after approximately engine revolutions, will determine if the misfire is still present. If the misfire is still present, the ECM will disable the fuel injector again repeating the process.
If the misfire is not present, the fuel injector will remain enabled by the ECM. Get Access to Factory Service Manuals. Need more help? Get the P Oldsmobile code diagnosed by a professional: Find a repair shop in your area.
Why is the Engine Light ON?
Repair Importance Level: 3.The PCM also monitors resitance in the circuit. If the resistance is excessively low or high it will set this code. Poor acceleration. The MIL will also be illuminated. Check for voltage at the fuel injector connector. It should have 10 volts or more. Visually check the connector for damage or broken wires. Visually check the injector for damage. If you have access to an injector tester, activate the injector and see if it operates.
If the injector operates, then you likely have either an open in the wiring, or a blocked injector. If you do not have access to a tester, swap the injector with another one and see if the code changes. If the code changes, then change the injector. Make sure you have the correct wire.
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Lexus IS250 and GS300 rough idle and/or P0301, P0302, P0303, P0304, P0305, P0306
If you have any doubt as to repairs on your vehicle, please contact your technician. Search for: Search.LEXUS IS300 ENGINE CODE P0301 P0303 P0305
What does this mean? Note: 1.