CEL: Random Multiple Misfire and other Bogging issues.

[bhadreshl]

First the CEL, mechanic says it could be the crank sensor, which I shouldn't worry about replacing.

I think it's the coil packs so I ordered new one's, possibly replacing tomorrow. Hope I get the spark plugs too so I can do it all at once.

I also get really sluggish acceleration, possibly due to this, but the symptoms are as follows. At 3-3.5k revs drop it into 1st, I can almost hear a squeak, but it even when throttle is fully depressed, it still bogs down. Starting at lower than 3k revs is possible, but still bogs down. It's almost as if the engine is still providing the torque to the wheels, but still the revs drop. Overall acceleration is still sluggish afterwards. I think it could be the following...
--timing
--throttle body and it's sensors.
--ignition

Some more detail. I disconnected the battery once and it would start up but no matter how much the throttle was depressed, it wouldn't go past 1500 revs. It ended up being that cleaning the throttle body fixed the problem.

Last week, I disconnected the battery again and when the engine was re-mapping the idle rev's, the engine kept turning off in neutral. When it was in gear, no problems. After the re-mapping finished, it has been running fine for a week, no CEL. Two days earlier, I got a CEL again and it's been sluggish ever since.

Any help is appreciated.

[silverstarmazda]

you might be bogging due to heat soak? maybe just maybe

[Default User]

Vacuum leak, MAF issues?

[bhadreshl]

Didn't even know there was such a thing, but reading up on it, you might be onto something. http://cjbfire.com/Heatsoak.pdf. If I'm understanding that term correctly, it's caused by coolant spraying into the engine and the ethylene glycol igniting. I recently did a head gasket replacement, due to the block being warped after uneven cooling; due to serpantine belt breaking. Maybe I'll have to watch my coolant levels very closely.

The sluggish acceleration (or bogging) did start after the head gasket, but the CEL was before that.

[Wes08M3]

Heat soak doesn't usually cause a CEL. And it's not all that common on n/a cars, especially if it's just sitting idle in the driveway, that's near impossible...

Here's what you need to do... READ THE CODE!!!! That's the most obvious thing to do, you can throw out a million different things it could be but actually reading the code will narrow down your search! Narrow it way down... You seem to have had this CEL for a while and you never thought to get it read? Instead you're just going to throw parts at it?

Anything anybody says, is just a complete guess. You have to narrow it down before you can start searching and finding common faults with regards to specific components. It could be a MAF, could be a TPS, could be an o2, could be ignition, the list keeps going... These are all totally different systems and reading the code will tell you which system it is! Otherwise you'll be scratching your head for a while.

PartSource reads codes for free.

[bhadreshl]

Went to my mechanic and pulled the code myself. "Random Multiple Misfire"

[Wes08M3]

Good! Sounds like you're on the right track... I'd be checking the condition of the plugs first. If they're in rough shape replace them, maybe just replace them anyway. They could've been damaged when the head was off. If that doesn't fix the problem then like you said, a coil might be the problem. Generally that code is ignition related. Had the same code in my Mazdaspeed Protege, the coil pack was the problem.

Usually that code even tells you which cylinder(s) the misfire occurred. Did the code reader give you that info? No need to go replacing all 4 coils if you don't have to.

[TheMAN]

don't drive the car until it's fixed! not only safety problem (hard to get out of the way), but you can easily melt the cat, which costs over a thousand to fix!

[silverstarmazda]

don't drive the car until it's fixed! not only safety problem (hard to get out of the way), but you can easily melt the cat, which costs over a thousand to fix!

that or cut it off LOL

[highlineMotors]

First the CEL, mechanic says it could be the crank sensor, which I shouldn't worry about replacing.

I think it's the coil packs so I ordered new one's, possibly replacing tomorrow. Hope I get the spark plugs too so I can do it all at once.

I also get really sluggish acceleration, possibly due to this, but the symptoms are as follows. At 3-3.5k revs drop it into 1st, I can almost hear a squeak, but it even when throttle is fully depressed, it still bogs down. Starting at lower than 3k revs is possible, but still bogs down. It's almost as if the engine is still providing the torque to the wheels, but still the revs drop. Overall acceleration is still sluggish afterwards. I think it could be the following...
--timing
--throttle body and it's sensors.
--ignition

Some more detail. I disconnected the battery once and it would start up but no matter how much the throttle was depressed, it wouldn't go past 1500 revs. It ended up being that cleaning the throttle body fixed the problem.

Last week, I disconnected the battery again and when the engine was re-mapping the idle rev's, the engine kept turning off in neutral. When it was in gear, no problems. After the re-mapping finished, it has been running fine for a week, no CEL. Two days earlier, I got a CEL again and it's been sluggish ever since.

Any help is appreciated.

And what kind of car is this?

[TheMAN]

this is a mazda3 forum, so he was talking about a honda civic

[Booostin]

Look at OP signature and you will see what kind of car it is.

[bhadreshl]

Got the code pulled again and more codes to play with:

P0446 - Evaporative Emmission Control System Vent Control Circuit
P0445 - Evaporative Emission Control System Leak Detected (no purge flow or large leak)
P0442 - Evaporative Emission Control System Leak Detected (small leak)

Mechanic says it could be the EGR valve. I'll have him thoroughly check though.

[bhadreshl]

Still struggling with this issue. Car now sounds like a tractor! Throwing a CEL almost every time I accelerate. Can't be good for engine but....still runs.

I tested replacing coil packs and fuel cap; but no change. I've also replaced: intake/TB gasket kit, EGR valve, PCV valve, Purge Solenoid Valve and still no results

The next thing is to go through the hoses. Is there a hose kit I can buy?

[TheMAN]

almost a year goes by and you're still throwing parts at the car? if you don't know what you're doing, take it to a shop... shotgunning parts on the car wastes money and time
there's hardly any way for us to help you diagnose and fix your problem over the internet... we can't hear or see what is happening nor can we look around the car over the internet

[silverstarmazda]

^+1 you do not want to go down the path of random parts....costly and no guarantee that itll fix the problem.

as for sounding like a tractor....sounds like you have a timing problem.... which can be a LOT of things... but start for the free check. look up "advanced timing mod for mazda 3" on google. the sensor might be out of its usual position by a lot. not common, but i can see the possibility of it being undone.