05 Mustang GT Misfire

[jetskier369]

My 05 Mustang GT as started misfiring, but is unfortunately not putting out any codes, to diagnose the problem. Misfire is intermittent, and seems to happen more when it is cold out. I took it by a shop, but of course at that time, it was running fine. So I was curious if anyone could tell me, what I should data log in order to help diagnose the misfire. I've been watching a few things, like the readings from the MAF sensor, fuel pump, and short fuel trim, spark advance. But was curious if there are other's I should watch as well, to help get it figured out. Wanting to make sure I'm not missing anything I should be watching. Any help would be greatly appreciated. Thank you.

[DiabloMatt]

aside from codes another thing that can show you is the short term fuel trim. idealy they should all be close to zero. if it starts missfiring, look for one of the short terms to go really far positive. reason for that is a misfire will put a large amount of unused oxygen in the exhaust and the senors will read lean and add more fuel. that will at least tell you what side it is on.


how many mile are on the plugs? might not be a bad idea to just change the plugs just because if they have some miles on them

[jetskier369]

I had the plugs changed maybe 5000 miles ago. So, it hasn't been very log since they were changed.

[DiabloMatt]

I had the plugs changed maybe 5000 miles ago. So, it hasn't been very log since they were changed.

ok just making sure. and no chance of water or anything in the plug holes?

just looking for things i have seen before.

[jetskier369]

I don't believe so. I did finally get a code yesterday saying cylinder 6 is misfiring. So i'm going to change the coil, and plug, and make sure the plug isn't white, and go from there.