Blinking CEL

Can anyone from Veeky Forums assist me? There seems to be a problem with my car, if I accelerate too hard the CEL starts to blink, when I had the car scanned it said it was a misfire but I had already changed all the coils and plugs, also when I get to 60 mph when the light is blinking, the car shakes a bit, any thoughts what the problem might be?

It's knock knock knockin on heavens door.

Bump

Could be a poor fuel issue user
How old is your fuel filter?

A blinking CEL means you have a misfire which causes damage to your catalytic converter. This is something that you should fix asap

Misfire. Most of the time a blinking CEL is used only for a misfire, and for good reason. Depending on the type of misfire, it can wreck your engine big time if left untreated.

As far as basic troubleshooting, go back to the basics of how the engine works. Air, fuel, spark. All in the right amount at the right time. If you've done coils and plugs, spark should be good, as long as there are no old wires to play funny business. That leaves us with fuel and air.

Typically, a misfire related to either of those things is a result of the ratio between them. You could have a dirty MAF causing it to see the wrong amount of air coming in and add an incorrect amount of fuel. A plugged or damaged fuel injector(s) could cause that issue as well. Post-combustion, the O2 sensor could have misadjusted a fuel trim if it's sending a faulty signal. Go through every system that regulates the amount of air and fuel that goes into the engine and make sure it's all cleaned and in working order. One thing that is often overlooked is the valvetrain. If you have VVT/L, that not working could definitely cause a misfire as the ECU expects a certain amount of air/fuel mixture at a certain time, and then the valves being open at a strange time could mess that up.

Another thing that's simple, stupid, and easy to fix is octane rating. Next fill up, try putting the highest octane you can buy in it. Even if that isn't the root of the problem, if your misfire is in the form of detonation (the kind that murders engines) it can at least mask the issue enough to make the car drivable while you do more research.

Misfires can be a pain in the butt to track down, so good luck! If you can get a scan tool hooked up to it there may be stored codes that can point you in the right direction if you write down the exact code(s) and post it here, so make that a priority to get done.

Try replacing the injectors.

Not OP but my CEL is coming on and off every few weeks. Once in a while when it's on, it'll flash for 5 seconds or so and then stop, and then the CEL will go away a day later.
Is my car fucked or could it be something like a sensor? I definitely don't feel any misfires when the light comes on or starts flashing, and the car's been running smooth the whole time.

do you have a mazda 3

No I have a 7th gen v6 Accord.

ah just wondering because I did a VIN check on my mazda 3 the other day and saw a bulletin about misfiring codes being bullshit due to faulty programming

fuel filter and air filter, change both.

Is it a honda accord by any chance

Sorry op didn't see this answer from you. Two possible things: your piston rings are fried and oil is seeping up causing a misfire, or your crankshaft position sensor went bad and now u need a new one plus a dealership to reflash your ecu for the new one. I had the exact same problem about a month ago with my sister in laws honda same gen but the 4 banger. Apparently it's we'll documented and should be available to be fixed for free at the dealership via recall. When u changed the plugs and coils was there oil on them? If not its probably just your crankshaft position sensor. Also, has your battery died recently or did u have a tough start on a cold morning or after leaving your lights on or anything like that?

My Honda burns a bit of oil. Enough to see the smoke on high RPM runs. It doesn't misfire. You'd have to be burning a shit ton of oil for that to happen.

That does make me think though, does the car lose coolant? Does the oil and coolant look normal? A blown head gasket could cause misfire, but it'd be at start up most likely from the gasket seeping coolant into the cylinder.

Crank pos. sensor isn't a bad guess, but it'd probably throw a code for it, wouldn't it?

I haven't changed the spark plugs myself. I just bought the thing recently and the last owner said he did spark plugs around 25k miles ago.
I tried checking myself but I'm wrench-retarded and couldn't manage the back spark plugs, but at least the front 3 plugs are alright.
Will recall repair at a dealership apply even if it's a 10+ year old, 2nd hand vehicle?

>but it'd probably throw a code for it, wouldn't it?

yes, yes it would.

maybe the plugs are the wrong ones for the car? Japanese cars are really picky about their plugs. Try putting some NGK plugs in there?

It should still cover it. When my sister in law was having the issue she was getting codes for misfire 2 misfire 3 and then random misfire and she got CPS once but it immediately went away. We did all the normal diagnostics checked and changed all the plugs to oem spec NGK checked all the coils, disconnected them while running to try to listen for changes and everything and cleared the codes. the cps code never came back but the other ones remained and the cel would blink and shudder the car into limp mode. Basically what ended up being the exact culprit was
>cps starting to go bad
>cold start on an old battery, cps doesn't register right reading due to low voltage
>misfires because now timing and shit is wrong due to CPS being wrong at startup.
>ecu can't fix this problem on its own for some stupid reason. Once it happens once your screwed and need a new cps plus a reflash. It's apparently 3 reflashes
>will only throw the cps code on that first initial startup but never again.
Her brother in law (not related to me) owns a shop and when I called him he knew exactly what the deal was since its apparently so common. I changed the cps out and honda dealer reflashed the ecu. Good as new. We could've gotten the part free thru them too apparently but we didn't know.

Why do you have to reflash the ecu? I've never heard of that before. Is it because the new CPS is a updated and altered part?

I'll give that a try and maybe contact a Honda dealership about it. Thanks.
Hopefully this doesn't end up being too expensive.

If you still have oil on your new spark plugs it's your valve cover gasket.

02 sensor does not cause a blinking CEL, it just stays on. the same with mass air flow sensors.

best bet is to get a code scanner and check it when the code is on.