Keep getting multiple misfire codes, normally different cylinders except on cylinder (0307), can this one be throwing off the rest
It started with what I thought was lack of fuel, tapped on the gas tank and boom fired up. That to me said fuel pump was going, had it replaced by a certified garage. Got it back it kept having misfire codes so did a almost full tune up, almost because the wiring for this truck is no longer made. The misfire happens some times and at different times. Like sometimes on rough start sometime on accelerating, and sometimes at idle. I have a regular scanning tool and i keep getting multiple misfire codes, sometimes 2 sometimes 5 more so with 6 but always with 7 (sometimes just the 7 cylinder). Now
Experienced mechanics share their insights in answering this question :
This may be a problem with the exhaust catalyst partly clogged causing excessive back pressure. There is a test where the O2 sensor is removed and the back pressure tester is put in the hole to see if the catalyst is clogged.
The computer should be scanned to see if you are running lean from bad O2 sensors or for some other reason. The coil may also be weak and not putting out enough spark energy. Have the system checked by a mechanic since this truck engine may have exhaust problems, engine carbon build up, cracked valve seats, O2 sensor problems, coil problems, camshaft and distributor cam gear worn problems. The list goes on and will require a qualified mechanic time to diagnose this complaint for you. If a shop or mechanic cannot figure it out then it may take a factory trained mechanic to be able to diagnose the problem down to one of the listed issues. The best thing to recommend is to replace all the tune up items first so these can be eliminated. This means coils, plugs, wires, fuel filter and air filter, and PCV valve.
How to Identify and Fix Common car Problems ?
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A misfire typically occurs when the timing of this ignition is off. P0307 indicates that cylinder #7 is experiencing misfires.
P0300 Random, Multiple Misfire Detected means that your car`s computer (PCM) detected that there is a misfire in random or multiple cylinders. Code P0300 is often related to bad spark plugs or spark plug wires but could be caused by a number of issues relating to ignition and the air-to-fuel ratio in the cylinders.
A leaky head gasket will usually cause multiple cylinders to misfire, especially ones next to each other. If you move a few spark plugs around and the issue stays localized within certain cylinders instead of localized to problematic spark plugs, you should check your head gasket.
P0300 indicates that two or more cylinders are experiencing misfires.
Driving with a misfiring cylinder is potentially dangerous. If you lose power while driving or a second or third cylinder goes out, this can cause you to get into a car accident, possibly injuring you and others around you.
Can a bad O2 sensor cause a P0300 code? Yes. As it is one of the most vital inputs to your car`s computer for fuel control, a sensor failure can result in an incorrect air/fuel ratio. In addition, it can lead to engine misfiring and set code P0300.
Yes. While the damage may seem small initially, the longer you drive with a bad oxygen sensor, the worse the damage will become. Eventually, you may experience rough idling, poor acceleration, engine misfires, an illuminated check engine light, and failed emission tests.
Good quality fuel injectors rarely cause misfires whereas, poor quality or faulty injectors cause destructive misfires. The vehicle can experience various misfires when a faulty injector is a reason; it can lead to a loss in acceleration, power, and reduction in fuel efficiency.
A leak into the intake port of a cylinder can cause a lack of fuel. Vacuum leaks on individual cylinders commonly occur around intake-port gaskets or vacuum-hose connections. Depending on where the vacuum leak is on the manifold, it can generate random or specific cylinder misfire codes.
The fault codes usually associated with a clogged fuel injector can range from misfire codes to lean codes. Fault codes associated with a clogged fuel injector are the P0300 thru P0308 series, which indicates the engine controller is seeing an engine misfire.
OBD II can give you an exact count of the misfires cylinder by cylinder (which you can find in Mode $06 with a scan tool), but it can`t tell you what`s causing the misfires. Every engine will experience an occasional misfire.
Other Notes About P0300
Driving with an unresolved P0300 code will almost surely lead to bad fuel economy and more money paid at the pump, not to mention the astronomical repair costs of a severely damaged engine if misfires end up causing more serious problems.
Misfire at Idle Only. Your car may drive perfectly fine but display signs of little hiccups or small misfires at idle. Generally, the cause of a misfire at idle is an incorrect air-fuel mixture. This can be caused by a faulty O2 sensor, a fuel injector that needs cleaning, or even vacuum leaks.
Other Notes About P0300
Driving with an unresolved P0300 code will almost surely lead to bad fuel economy and more money paid at the pump, not to mention the astronomical repair costs of a severely damaged engine if misfires end up causing more serious problems.
A clogged or failed exhaust gas recirculation or crankcase ventilation valve or faulty oxygen sensor can send the wrong signals to the computer and cause misfires.
The fault codes usually associated with a clogged fuel injector can range from misfire codes to lean codes. Fault codes associated with a clogged fuel injector are the P0300 thru P0308 series, which indicates the engine controller is seeing an engine misfire.
Relevant Questions and Answers :
the most relevant questions and answers related to your specific issue
Keep getting multiple misfire codes, normally different cylinders except on cylinder (0307), can this one be throwing off the rest
ANSWER : This may be a problem with the exhaust catalyst partly clogged causing excessive back pressure. There is a test where the O2 sensor is removed and the back pressure tester is put in the hole to see if the catalyst is clogged.
The computer should be scanned to see if you are running lean from bad O2 sensors or for some other reason. The coil may also be weak and not putting out enough spark energy. Have the system checked by a mechanic since this truck engine may have exhaust problems, engine carbon build up, cracked valve seats, O2 sensor problems, coil problems, camshaft and distributor cam gear worn problems. The list goes on and will require a qualified mechanic time to diagnose this complaint for you. If a shop or mechanic cannot figure it out then it may take a factory trained mechanic to be able to diagnose the problem down to one of the listed issues. The best thing to recommend is to replace all the tune up items first so these can be eliminated. This means coils, plugs, wires, fuel filter and air filter, and PCV valve.
EGR code, Cylinder 4 misfire code 0304 detected.
ANSWER : Hi there. The Exhaust Gas Recirculation (EGR) valve may be not designed for the emissions requirements for U.S. standards. If the EGR is pulling from cylinder number 4 and after replacing the EGR and the computer detects a misfire, then the EGR is malfunctioning and not responding. When you close off the tube to the EGR and the EGR light comes on and the misfire light goes out, then the EGR is not responding to your emissions system. I recommend replacing the EGR with the OEM specified part for the engine and all of the issues should go away. If you need further assistance with your misfire and EGR, then seek out a professional, such as one from Your Mechanic, to help you.
One month ago cel came on I changed spark plugs to after market plugs. One month later cel on again with misfire code.
ANSWER : If the spark plugs hadn’t been changed until 130k, it was time for the to be replaced anyway. This is probably why the dealer went with that repair as worn spark plugs can cause misfires. Ignition coils are another part that may fail and cause misfires when they malfunction. A compression test and cylinder leak-down test will show if there is a problem with the valves. You can try having the coils replaced and the valves adjusted by the dealer. Consider hiring an experienced technician like one from YourMechanic who can come out and conduct the same tests as the dealer could and determine the cause for your check engine light.
EGR code and Cylinder number 4 misfire detected.
ANSWER : Hi there. The Exhaust Gas Recirculation (EGR) valve may be the wrong one or the cheap design could be not designed for the emissions requirements for U.S. standards. If the EGR is pulling from cylinder number 4 and after replacing the EGR and the computer detects a misfire, then the EGR is wide open and not responsive. It is clearly the EGR as when you close off the tube that the EGR light comes on and the misfire light goes out. I recommend replacing the EGR with the OEM specified part for the engine and all of the issues should go away. If you need further assistance with your EGR and misfire, then seek out a professional, such as one from Your Mechanic, to help you.
Code said cylinder 1 misfire, cylinder 2 misfire, o2 sensor misfire?
ANSWER : Without checking the ignition coils and spark plugs myself for proper spark output I would say the engine is misfiring and may be the coils and plugs. It is also common for the valve cover gasket to leak oil into the spark plug tubes shorting the coil and spark plug out so it cannot fire. The check engine light is flashing due to the misfire is active and additional catalyst damage can happen if you keep driving with the misfire and raw fuel dumping into the catalyst. I would recommend having a mobile mechanic like one from YourMechanic come and do a through diagnosis to see if the valve gasket is leaking into the spark plugs and caused damage to the coils and spark plugs. If it is leaking then the valve cover gasket should be replaced with the spark plugs and contaminated ignition coils replaced then computer codes an be cleared and the vehicle road tested for any other problems from driving the vehicle with the engine misfiring.
Misfire cylinders 4 and 7.
ANSWER : You need to check the PCV tube that goes behind the intake and connects into the back side. The hose can get a leak in it, causing a vacuum leak on the back side. This will create lean conditions that may be worse for cylinders 4 and 7 specifically on this engine.
If the hose is good then try and have the injectors replaced or cleaned for these two cylinders. You could swap them with different cylinders to see if the problem moves along to the other cylinder, doing so will help pinpoint the issue.
If you decide to get the car looked at, consider YourMechanic, as a certified technician can come to your location and diagnose your car’s misfire. An accurate repair can then be made once the problem has been pinpointed.
03 pontiac vibe getting misfire codes random and all 4 cylinders previously before some repairs it was cylinder 1 and 4 or 1 and
ANSWER : Hi there. It is quite possible that the source of all of these issues are faulty or clogged fuel injectors. When this happens, it can cause misfiring and poor fuel economy. It might be a good idea to have one of our professional mobile mechanics come to your location and complete an engine is misfiring inspection to correctly isolate this issue and recommend the right repairs.
Misfire on cylinder one
ANSWER : A misfire to cylinder 1 may be a fuel pressure regulator sensor problem but it is most likely due to a clogged injector on number one. You will need to scan and view data to see if fuel pressure sensor is needing replacement first. Then have the injectors cleansed to see if the codes go away.
I’d suggest you get this looked at by a qualified technician who can perform these checks to diagnose your Check Engine Light and make the appropriate repairs to your vehicle.
