so after work today it came on and started flashing and i lost power....
i got home i scanned the car and it was again a misfire code, cylinder 3 and 5 misfire
i check coils 5 and 6, both making the snapping noise, i checked the fuel injectors they all feel and seem to be working (there ticking) i then check the cai and did notice that the actual filter was loose. its a none oil filter. im going to do a compression test tomorrow to count that out(hopefully) so maybe tightening the air filter down will help....

i also went over the vacuum lines and didnt see or hear anything, i will double check with brake clean

 

the loose air filter may be part of the issue. it would be sucking in way more air causing it to run lean. Fingers crossed. ket us know how the compression test goes

 

there is also a TSB for misfiring issue after changing plugs. not sure the number, but I do remember reading that the ecm needs reflashed with newer code? ive been thinking of having this done but things are running fine for now.
here is a list of TSBs you can browse thru. credit for list to other forum. good luck

http://www.stangpit.com/info/tsbs-fo...2009-mustangs/

 

ok its back...


so after i re-tuned it, i got on it and the misfire code came back. i deleted it drove it again, then a cylinder 4 mis came up...

i decided to have one of my good buddies/mechanic check it out. we did comp test-good

check for vacuum leaks- none

he did see on the modus that is was missing but we couldn't find anything causing it.

he told me too try a different tune, one before the mis happened. it worked for a while came back today, first as a multiple, then cylinders 3 and 5.

my buddy is thinking its the camshaft position sensor. i think thats what ill do next. what do you think?

i just don't know what else it could be.

i also read that alternators can cause a misfire as well. any thoughts??

 

this is ridiculous...

replaced both CPS today, drove it felt fine no miss. then i left work got on it and it popped, i couldnt feel a miss. scanned the code now its only a clyinder 3 miss.

i cleared it, see what happens. maybe crank sensor??

this is frustrating

 

the alternators can throw out a cam sensor code, i know it sounds peculiar but you don't seem to have that code.
If the crank sensor or cam sensors were bad, the usual symptom is cranking with no start. you've definitely got a strange one. are you sure you used the correct spark plugs? You could also have carbon buildup on a valve causing a slight miss.
now you need to see if the coil is getting power all the time. its hard to test. it could be getting a faulty signal from the ECU and a new ECU may be the fix, but thats usually a last resort. Sorry i can't be of more help but please let us know what you decide to do. and of course don't hesitate to ask questions.

 

i get all my parts from american muscle. they were stock motorcraft plugs (maybe thats the problem) and another thing is that it only seems to mis on cold start up at low idle. idk if that helps.

im going to have another mechanic look at. see what he thinks.

ill keep you up to date. thank you

 

just thought i would let everyone know, i got the problem fixed!!!

the alternator was cause. it was putting out about 13.1-13.3 volts
took the pullys off to see if it would go up more. it didnt. replaced the alt. went up too 14.2, havent seen the light since.

thanks for the help guys!

 

The OE alternator has been a chronic issue with these S197's. Glad you found the problem... finally.