[00GTpony]

Need ur help guys....... my girlfriend has a 99 mazda 626, its been throwin a cylinder 1 misfire code.. The car studders bad on take off, or on a load... Also shakes wen sitting. I changed the plugs, wires, fuel filter, and coil... What else could it be.. Im going crazy. Please help . thanks

[Rusty67]

Could be a problematic injector. Dump some fuel injector cleaner in and see if that helps.

[BobHyatt]

Originally Posted by 00GTpony

Need ur help guys....... my girlfriend has a 99 mazda 626, its been throwin a cylinder 1 misfire code.. The car studders bad on take off, or on a load... Also shakes wen sitting. I changed the plugs, wires, fuel filter, and coil... What else could it be.. Im going crazy. Please help . thanks

Check the plugs to see if one is off-color. A bad injector could easily do this and I just helped a friend fix this exact same problem on a I-4 honda accord. #4 was misfiring, and on inspection was completely black. Injector was sticking open / not closing properly.

Easy enough to fix, buy one injector and a complete set of injector O-rings as it is too easy to nick one and get a leak when removing the fuel rail.

[96GTstang46]

SEAFOAM!!!

Seams to help out alot sometimes with weird problems like this..

[00GTpony]

ya im going to throw a new injector in today and see what happens. its gotta be the injector thats the only thing left.

[BobHyatt]

Originally Posted by 00GTpony

ya im going to throw a new injector in today and see what happens. its gotta be the injector thats the only thing left.

There are other possibilities that are pretty rare. Worked on one where two of the injector wires had cracked and were shorting together. So both injectors were firing twice making for a rich condition. I was suspicious in that it is pretty unlikely to see more than one fail at the same time unless one runs without a fuel pump and fills up in the backwoods somewhere.

[tomustang]

Refer any other auto tech questions to this thread next time http://forums.stangnet.com/forumdisp...ysprune=&f=237


If you want to check the injectors, swap it out to another cyl and see if the code goes over to it, insted of buying an injector. If you are buying one you should buy all of them and replace them all, so you can have all of them on the same page

[00GTpony]

I changed the injector today with a new one, and its still misfires bad..... studders rele bad and stalls.. wen it studders on take off, there is also a knocking sound comming from the motor.. Im going crazy

[03ghoststang]

how many miles on the car?

[00GTpony]

84,000

[03ghoststang]

So you replaced the wires along with cap and rotor...... check and see if you dont have any wires in the wrong firing order

[00GTpony]

def right order....no cap , just one big coil

[BobHyatt]

Originally Posted by 00GTpony

def right order....no cap , just one big coil

but there are 4 connectors on the coil, and one can be wrong.

knocking sounds bad however...

[00GTpony]

coil is labeled with numbers, and the wires are from left to right 1 - 2 3 4

[Rusty67]

Not sure how computer controlled the car is but can you check the timing with a timing light to make sure it is on ?

[00GTpony]

ok, so there were brand new motorcraft plugs in there that autozone recommended, and someone on another forum told me the cars only like NGk plugs, so i put them in and the car runs great, i dont get it.

[Darkwriter77]

I know Ford and Mazda have ties but ... WTF? Motorcraft plugs in a Mazda? Someone at Autozone doesn't know how to read their friggin' parts screen.

Having worked there, myself, I know that it'll list just about ALL brands for ANY make, as long as there's something listed that will cross-reference to it. Therein lies the problem. Cross-referenced plugs are not always a direct fit or replacement. The Motorcraft plugs you had in there might have been a totally different heat range that placed the electrode so far back into the plug hole that it wasn't deep enough into the combustion chamber to actually get a consistent and/or effective ignition. Why it would only do it on one plug is kinda weird, but still ... if you replaced them with NGK's or Denso plugs and THEN it worked, I'd say that was likely the case.

Import cars need import plugs, and domestic cars (generally) should have domestic-brand plugs - not because of performance differences and such, but because most Asian imports use Denso or NGK plugs from the factory. Likewise, most GM cars use AC Delco plugs, most Fords use Motorcraft, and MOPAR uses ... uhhh ... whatever they have laying around, I guess. But in trying to cross-reference an import plug to a domestic, they just try a "well, that's the closest fit we make" kind of approach, and that can yield some crappy results.

Glad you got the car workin' good, though. Are you taking the injector back? I would - it was the 'Zone's fault for having crappy cross-referenced plug numbers in their system in the first place (and a dummy working behind the counter that thought Motorcraft is OEM for Mazdas).