2007 Mustang GT P0308 Idle Problems - Cylinder Misfire

[G9-07-Eddie]

Been having this issue for a month now, it started like right after I was driving one day last month and I had to slam on the brakes dont know they are related,Anyways my idle is like off my rpms go from I guess like 800rpm or whatever its normal and drops to like 700-750 range and does it for awhile I'm at a light, or when I start it up. It been doing it more frequent now.So any help would be great as to what it is.It feels like its hesitating somewhat i guess.But only when I'm stopped while driving its fine.so need all you gearheads let me know what you think?Been talking to Cris and Dan and they think it might be my throttlebody or my MAF sensor or both.

[greenscobie86]

Any sort of vacuum leaks?
Does the idle change when you operate the heater?

Have you cleaned the IAC(not sure if 3v motors have them?)

[G9-07-Eddie]

have had the heater on, and it has done it.

[greenscobie86]

I would venture a guess that maybe an emergency braking condition could have ruptured a part of a vacuum hose somewhere and is now causing your surging idle issue... I would inspect vacuum hoses, and take a look at the MAF(switch with someone for a test) and also clean the IAC as well...

Your car is tuned right? Bring it back to the factory tune to see if that changes its behavior...

[Bandit]

When is the last time you ran some injection cleaner thru it? I'd run some Lucas fuel treatment thru it and maybe a can of dry gas as well. I also try loading the stock tune back and then reloading the performance tune back in.

[PWRBY4D]

Originally Posted by greenscobie86

I would venture a guess that maybe an emergency braking condition could have ruptured a part of a vacuum hose somewhere and is now causing your surging idle issue... I would inspect vacuum hoses, and take a look at the MAF(switch with someone for a test) and also clean the IAC as well...

Your car is tuned right? Bring it back to the factory tune to see if that changes its behavior...

if it was a vacuum leak it would be doing it all the time.... plus i feel that the brakes would also have a different feel... doesnt hurt to check though i guess... anyway... plug your tuner in and look to see if you are throwing a code..

[G9-07-Eddie]

will do that tonight to see if they are any codes? and check for leaks and will check the maf to see if its dirty or something loose. thanks for the input guys.anyone else feel free to throw in your 2 cents.will get that stuff on the way home as well, thanks guys

[PWRBY4D]

also check to see if your cold air intake is on secure and you dont have any air leaks from the filter to the tube and also at the tube to the throttle body.. also check both pcv lines going ito the throttlebody and intake manifold... they will click on/off. i have heard of a few people with s197's having to clean the MAF with a cleaner. Also Throttle Body Position sensor could be bad from what Da told me the other night they are also a known issue (Dan actually thought of that one so I will give him credit ) my guess is maf is dirty... i think that if it was the something else it would be much worse... good luck.

[G9-07-Eddie]

ok will let you know how i make out tonight with it.

[Hotshot]

+1 to what chris said. Inspect the CAI to ensure a snug fit, spray down the MAF sensor, clean the TB with TB cleaner. You've got 60k miles and doing these things helped my similar issue i had at 20k miles.