P0300 Random/Multiple Cylinder Misfire Detected...?
 

2002 Protege had a recent top radiator hose split that fogged up the engine compartment.

Replaced the hose and got a P0304 misfire in cylinder 4 code.

Switched the coil packs and then got a P0302 misfire in cylinder 4 code.

Ah ha, I thought, replaced both coils and both wires.

It runs great, a little bumpy while in drive at red lights

But now I'm getting the P0300 Random misfire code when the check engine light comes on.

I keep clearing the code and turning off the check engine light but it keeps coming back on after about a half hour of driving.

Other than new plugs, is there anything I should be checking or certain contacts that need cleaning?

I'm thinking something is not happy, or has a dirty connection from being fogged up with steaming anti freeze/coolant.

Thanks in advance for any ideas on what it could be

I would check all connectors that plug into coil packs and any other sensors anything basically with a electrical connector. If you say the whole engine compartment got soaked with coolant maybe somewhere water has gotten into a connector and is wreaking havoc on the system. Check alternator too maybe its gotten in there or in the plug for field. Use a air can and dry everything out and see if that helps. You never had any codes or problems before the hose burst ? So it obviously is happening now after the burst hose good luck

FYI

P0300 Random misfire
P0301 Cylinder 1 misfire
P0302 Cylinder 2 misfire
P0303 Cylinder 3 misfire
P0304 Cylinder 4 misfire

P0300 on any ECU controlled vehicle is the worst to get. It means that there is no direct cause and even a serious of anomalous issue can generate this. Also you keep clearing the DTC and no mention of looking at your monitors. That may be a clue to help solve your problem. But I would STOP swapping all those ignition parts around until you get closer to solving or have a better idea what you are looking for. You may be creating more issues which is what I can see at this point.

Same issue
 

I recently bought a mazda familia BJ Sport, had intermittent idle issues and felt lumpy on drive. Removed engine cover and removed plugs, check gaps and replace reinstall still no go.

misfire can be heard when you run car, was sitting and watching why it jumps and sputters and saw an arch near oil filler, there was a break in ignition coil.

replaced coil wire and all good.

hope u can figure out what’s going on with your car… good luck

Another posibility?
 

I am wondering if it could be the "Pulsation Damper"(also called a Fuel Injection Pressure Damper)

In another thread (link below) someone else solved a similar problem by replacing this small but pricey part.

https://www.mazdaforum.com/forum/maz...rotege5-20233/

Anyone else ever change one?

Was hoping someone with some experience had any advice with the crush washers involved.

Thanks everyone! :-D
https://cimg0.ibsrv.net/gimg/www.maz...bfc9ba2ba7.png

You can try getting one from wreckers it would be alot cheaper up to u. But ur throwing parts at it does the car do what that post says? I would get the pressure tested to see what pressure you have and you should be able to see if its up and down and if it is doesnt mean for sure that this would be it. Could be a fuel pump thats weak namely the brushes inside it not sure if youve checked that yet?Good Luck found this in my manual P300 :• CKP sensor malfunction
• CMP sensor malfunction
• Ignition coil malfunction
• High-tension lead malfunction
• MAF sensor contamination
• Excess air suction in intake-air system (between MAF sensor and dynamic chamber)
• Fuel pump malfunction
• Fuel pressure regulator malfunction
• Fuel line clogged
• Fuel filter clogged
• Fuel leakage in fuel line
• Purge control solenoid valve malfunction
• PCV valve malfunction
• EGR valve malfunction
• Vacuum hoses damaged or improper connection
• Related connector and terminal malfunction
• Related wiring harness malfunction
• Poor fuel quality

Wow, thank you, that's alot, I'll try to run the list.

This all started AFTER the top radiator hose blew and blasted the engine compartment with whole bunch of antifreeze steam. #1 coil pack and the passenger side of the engine compartment seemed to get the brunt of it.

I've changed both coils / wires, installed new NGK plugs(double checked the gaps & dielectric greased them all), unplugged every electrical plug and sprayed them with contact cleaner before reconnecting them, replaced the leaky valve cover gasket and of course the PCV broke and was replaced, cleaned the MAF sensor and heavy dosed it with lucas injector cleaner.

It runs pretty good until it's time to the climb the steep @ss hill to get home.

That's when its gets confused about what gear it's supposed to be in...

It will rev really high but only go 20 to 25 miles and hour up the hill until you let off the gas and it changes gears.

Then the idle is right but it has no power or speed (again only 20 to 25 miles an hour)

Tranny fluid is clean and clear with no funny smells. Car only has 118k miles on it so I think it's ok.

After all this It runs a lot better but still isn't right.

I've googled car exorcism's and trying to book a priest to cast out the demon gremlins...