well, i got in my mustang to take my girlfriend home, and as i was pulling out of my driveway i depressed my clutch and the mustang shuttered as if it were about to stall, only for about 1 sec. then i get to the first stop sign, and same thing, as im slowing down to a stop around 5mph i went from 2nd back to 1st, and again it shuttered as if it would stall. it did this for another 2 stop signs where i would slow down and downshift to first and it would shutter. when i got onto the main street it seemed fine, after on the road for about 5 min i came to a traffic light where i stopped. i was just talking to my girlfriend and glanced at my Rpm's... the needle was flat 0rpms, then i noticed i didnt feel the vibration in the pedals or stick, the engine died on me. i turned the key off and back on, and it started up fine. it was weird cause i didnt stall it, it didnt lurch foreward, and the battery was fine cause the radio and lights were on the whole time. i dont know what happened, i proceded to take my girlfriend home with no problems, which was about 17 miles, but when i got back to my house's area it began to shutter again when slowing and downshifting. what could this be? any ideas would help.

 

It sounds like your RPM's are dropping to far, when was the last time you pulled and cleaned the TB and MAF sensor? Also check your intake make sure you dont have any leaks, mine did something similar and I had found a piece on my intake had come loose. If your not getting a CEL then these are the first things I'd check.

 

Could be a dirty MAF and/or TB as Mike mentioned or some bad fuel. Clean it all up and run a can of SeaFoam thru a tank.

 

^ what they said. It happened to me once when I still had the stock airbox. I looked under it and don't know how, but one of my rags was stuck in the little round hole at the bottom of the airbox blocking the air flow. Took it off and it was fine.

Oh, and why do you downshift to 1st gear ? I never went that low. the lowest I downshift to is 2nd gear. never felt the need to slow down that vioently or hear my exhaust sputter.

 

The exact same thing happened to me when I had my GT and it ended up being the TB..

 

i pulled my airbox, looked through it and seemed fine, no obstructions, after i reinstalled the airbox it wouldnt settle on an idle for about 5 min. it would be at 1k and slowly drop to 500 then quickly raise back to 1k as if i taped the gas. it seems fine now though, but im still closely watching the RPM's. how do i clean the MAF? and TB, i heard our TB's are sensitive so im not sure if i really want to touch it.

and as for why i shift down? i normally dont on flatter areas, but i live in a hilly area and my V6 engine needs the extra umpff to push these 20's up the hill.

 

don't worry about the downshifting...I always do it. Only time I don't is when I have to suddenly stop. the trick is blipping the throttle to where motor rpm's are roughly where they would be once the car is in the next lower gear. not many people get taught that little trick.


as for the sputtering and weird rpm changes...clean that MAF out. simply unbolt it, and be very careful with the wiring. I used alcohol cleaner...there are products specifically out there for TB cleaning..but I wasn't in the mood to go find it. So rubbing alcohol did the trick for me.


it's usually the simplest answer to a problem. hope that is your issue

 

Use a MAF cleaner for the MAF and be sure to disconnect the battery before starting maintenance. MAF sensor is on the intake tube after the airbox, is 2 torx bit #20 screws I believe. remove and disconnect. I use CRC MAF cleaner for the MAF just spay thr MAF all over a bunch of times(per the directions on the can). Dont brush or wipe any of the wires inside just spay them clean it will evaporate. I use CRC throttle body cleaner for the TB just make sure you use one that is safe for teflon coated TB's like CRC. The TB is 2 plugs and 4 bolts/nuts not including the removal of the airbox but is a simple straight forward job. If I were you I'd invest in a haynes manual which will help keep you on track and if you get stuck thier is always here. When you are finished reconnect the battery and start her up follow the idle learn procedure in the owners manual and you should be all set. Even if you take your time and go slow you should finsih both jobs within an hr or so.