Keep having Misfire issue.....

mp5build2013

Member
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Mazda, Protege5 02
well i just spun a rod bearing, and have the crappiest credit EVER lol so getting a new car was not an option, im overhauling it. I changed everything on the car when it was misfiring, but honestly.. if i had to point at something fishy about the issue/car, its the MAF. everytime i messed with it, the misfire would change to a different position.
for example, if the car was misfiring when taking off, lets say 2100 rpms and i would go mess with it, it would change to a different rpm when the misfire would occur. i bought a MAF off ebay and my dog got to it before i did, i figured she shook the crap out of it so i threw it on just for kiks. the car felt better, but the missfire had not gone completely away. after about 120 miles tho, no more missfire.after that i NEVER touched the maf again! lol it ran great till i spun the bearing, i drove it hard tho so it was not unexpected. im bummed, but im overhauling it and leaving it BETTER than before.(removing VCTS, painting all the parts and engine, cleaning up the bay and wires, and removing ac and cruise since i dont ever use them.
Good luck with it bro.
"wherever you go, there you are"
 

zizaspeed

Member
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2004 RX8
dang man how'd you do that? were you just pushin it an all the sudden......BOOM ? lol

Yeah I'm at a point now where as long as it's driving okay, then i'm good. I do need to take care of this stupid header rubbing against my oil pan though......it's so annoying when I'm just at a stop and my car from the outside especially sounds like it's falling apart.
 

kosteniuks17

Member
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Mazda Protege5 2003
If your still having the misfire issue i would try a few small things. I have literally the same exact setup (ebay sri, header, etc) and i remember after installing my ebay short ram I got the cel and took me a few day to figure why i kept getting p0300 and i think p0302. It was so obvious I just didnt notice it. when installing the rubber coupler from the intake to the actual throttle valve connection, (like the metal connection going into the engine). I noticed I didnt put the coupler all the way over the connection. There was a tiny tiny crack at the bottom of the throttle body where i didnt get the coupler all the way over it and it kept throwing misfire codes. I would make sure you dont have a tiny gap from your intake connection to the engine. After i finally fixed that i got misfire again. Anyways dumb ass me i later noticed that when installing the intake i pulled the little rubber hose connection that connects to the hood. There one line on the left (facing the engine bay) that should connect up into a nipple on the hood. After i connected the rubber tube the cel dissapeared. It might not that be easy for you, but that was my first install on a car other than spark plugs. I would clearly check for any vac leaks on your intake and make sure the rubber couplers are fully covering the throttle body connection and also make sure you have that connection going to the hood. Also if you reoriented your solenoid thingy (forgot whats it called) ive heard people saying that the solenoid that sits on top of the stock intake needs to be sitting the same way it was before otherwise it could cause problems. Just take 10 mins and let me know if that might be your misfire problems, I really do think you dont have your rubber coupler fully on the throttle body opening causing a small difference from what your maf is saying compared to what your ecu is saying. Or something like that haha, sorry for the very bad mechanical terms.
 
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mp5build2013

Member
:
Mazda, Protege5 02
dang man how'd you do that? were you just pushin it an all the sudden......BOOM ? lol

Yeah I'm at a point now where as long as it's driving okay, then i'm good. I do need to take care of this stupid header rubbing against my oil pan though......it's so annoying when I'm just at a stop and my car from the outside especially sounds like it's falling apart.

pretty much! lol i was driving and on a turn it spun out. I honestly think it has something to do with my front motor mount being broken in three pieces. it probably jerked waay to much :( and yea bro! i feel you with that rattle! now that the header is out again im going to wrap it and grind down that section of the header thats banging, if i dont get to grinding it in time, ill just jam some of the header wrap in that little crevise to keep it from banging. but i think im am going to gring that down. Just in case it helps, if you attempting to take off those 2 bolts at the bottom of the header and theyre rusted and siezed on, remove the pipe from the front exhaust hangers, i ripped mine right off attemtping to remove the bolts with a breaker bar.