Engine misfiring

Hi Sargeandy,

This sounds more like a fuel issue. the P0300 code is a multiple cylinder misfire. This means that the one cylinder can misfire and then the next time it does not but a different cylinder misfires. Basically, this is a misfire that does not have any consistency to it.

There are a number of things that can cause this but the most common cause is the fuel system because we are looking for something that effects all cylinders not just one.

This could also be a coil but again, this is less likely than fuel.

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

I would suggest starting with getting the fuel pressure while this is misfiring. If you have low pressure then it is either the pump or the regulator.

Let me know what the fuel pressure is and we can go from there.

https://www.2carpros.com/articles/how-a-fuel-pump-works

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Hello. i just bought the car listed above. the following codes came up along with the check engine light: 0300, 0301, 0302, 0304, 0314. Could someone shed any light please?

P0300 - Random/Multiple Cylinder Misfire Detected.
P0301 - Cylinder 1 Misfire Detected.
P0302 - Cylinder 2 Misfire Detected.
P0304 - Cylinder 4 Misfire Detected.
P0314 - Unspecified cylinder misfire.

We do not have service information for your brand, and you did not list an engine size so I cannot look up which type of ignition system your car uses. The typical suspects for multiple misfires include worn spark plugs and wires. Some cars have known problems with ignition coils too.

Car is misfiring and engine light is showing. Did the pedal test which shows a fault with cylinder 2. Have replaced the spark plugs and coil pack however still having the same problem. Could it be the Rocker cover?

How many miles are on the engine? Have you checked compression? Have you checked the injector to make sure it is good?

Its 86000 miles. Not checked those things, is it easily done?
Have taken it to the local garage this afternoon for another diagnostics and they are stumped as still showing cylinder misfire. Have been told to take it to Vauxhall where im sure they will charge a small fortune!

If you remove the #2 spark plug, is there spark to it? If there is, there is either a problem with the injector, wiring to the injector, or low compression in that cylinder. It isn't hard to check.

First, remove the plug and check to see if there is a hot blue snapping spark to it.

Here are directions for checking spark, fuel injectors, compression...

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

Do these checks and let me know what you find. You will need a few tools, including a compression gauge. Most parts stores will lend or rent them to you.

It started to judder on low revs would not start next the morning. I tried pedal test, I have done all the basic checks nothing. started on towing eventually still running uneven and juddering on low revs for about ten mile parked. It will not start. I have been advised to clean the egr valve, but unsure its location and how to do it . I am willing to try as quite knowledgable with cars, but this has got me baffled i am quite desparate now as I have tried almost everything. Any advice appreciated. Also could cooking oil be the problem as I ran out of diesel quite far from home? This was about two weeks ago I used it as an emergancy. Thanks

Hey Bev,

It sounds like the fuel filters need to be changed or the injector/fuel pump is going out which has been a problem with those cars. Also if you have a fuel dryer I would add that to the tank because moisture in the fuel can cause the problem;em you describers as well.

Let me know what you find

Best, Ken

Hi ken sorry for late reply still having problems its now running on 3 and 4 pots 1 and 2 are off .dont have a fuel dryer mate theres black smoke coming out thanks for yr advice on changing fuel filters and injectors got some imrovement from that cheers but still baffled its booked in garage for monday but would appreciate any further advice thanks ken

Hi Bev,

when one of the cylinders is not firing is one of two tings, low compression or no fuel getting to the cylinder. If you can do a compression test over the weekend it might help narrow it down.

Let me know what happens

Hi ken dont have equipment for compression test and unable to get anywhere. I dont think fuel is getting to cylinder

Yep, this will be an injector pump problem, pretty normal failure for diesel engines.

Cylinder four misfire.

That is way too much information to digest. With absolutely no test results, clues, or observations to go on, about all you can do is replace the spark plugs and wires and hope for the best.

Replaced spark plugs and ignition coil pack. No change engine still
misfiring.

Next you will need to pursue the less-common causes. As a test, consider switching two injectors. Erase the fault code, then see if it sets again for the same cylinder or the one you moved the suspect injector to. This works too for spark plug wires, spark plugs, and individual ignition coils when those are used.

Next would be a compression test. If you find it is low on cylinder four, a "cylinder leakage test" will identify why it is low. I can describe that in more detail if it becomes necessary. The tester can be hard to find. A lot of shops do not even have one.

Timing is also critical, but that is not going to change for just one cylinder, so we can forget that.

Electrical problem
2001 Vauxhall Astra 4 cyl Two Wheel Drive Manual

hi im having a problem with my astra, last week engine management light came on and started flashing so i took it to the garage they put a new set of vauxhall spark plugs in and now the fault has came back could anyone advise me on how to sort this problem as its been happening for a month or so and costing me a fortune with the diagnostic checks any advice would be appreciated,the light flashes when i put my foot down as soon as i take my foot of the gas it stops flashing.also ive replaced the coil pack too.regards john

replace the ignition wires .. swap number 4 injector with number 1, 2 or 3 injector .. see if the misfire codes changes to that pot ?

thanks for the reply dave i changed the fuel filter and its fine for now checked all the plugs and they all dry so hopefully the problem is resolved il keep you posted as to what happens regards john

thanks for the update .. keep us posted !

hi dave ive been informed by the garage that the misfire aint a misfire its the knock sensor pinking,could you tell me if it can be replaced without taking the timing belt off?

It is unusual for a knock sensor to go bad .. generally the knock sensor will pick up on a "knock" a harsh detonation .. this is what it is deigned to do .. if you get a knock sensor code .. then generally it is doing it's job ? it's picking up on a knock which is caused by something else ? (engine running hot/rich or lean fuel detonation etc.) could you please supply the fault codes the car is giving ..

hi dave its not showing any codes but they said its the knock sensor i can feel it thru the accelerator sounds like a misfire,this is really getting on my nerves now had new coil pack new plugs and the garage still cant sort it out the temp on the car runs at 88 when warmed up doesnt go over 90 and seems to be running a bit rich too maybe i should get it to a different garage as they dnt seem to know whats wrong but i also know if its pinking can damage the engine and im all out of cash now,frustrated aint the word thanks for yor help in advance.regards john

Hey. I do not think you have a problem with the knock sensor .. did you try to swap number 4 injector with number 1, 2 or 3 injector .. see if the misfire codes changes to that pot ? .. try this and let me know ..

car chugs when accelerating there is an orange light that comes on

the orange light is telling you there is a fault in the emmisions sytem .. you need to have the car plugged into a vauxhall diagnostic computer or equivalent to locate the exact cause of the "chugging"