well ive had the car for about two weeks now and i love it. only problem is that its acting up just a little...it started on this tuesday...i was leaving for work and my car wouldnt start. the engine started up but instead of going all the way on it kind of sputtered off at the last second. tried a couple more times with the same result. i took another car to work and when i got back i started the stang with no problem. thurs morning i go to start the car and it does the same thing but when i tried the second time it finally started up. its done the same thing every time since...either stall the first time and run on the second startup or almost stall out and finally start before it stalls.

i dont really know how to better describe the problem...the engine goes about 75% of the way on and starts to rumble but then all the sudden the tach drops and it stalls.

any thoughts? id really appreciate the help...

 

I would check your IAC. They are known to go bad on the 4.6's and cause problems with starting. Sometimes they can be cleaned, but often need replaced. Sounds like yours may be sticking.

 

dumb question...what does IAC stand for? i know theres that intake part thats plastic on the 99-00 gt's and sometimes causes problems...

 

update...i did a lot of research on idle air controller problems and it seems like many mustangs have them. i actually found an iac at advance auto parts for about $40. but today when i started the car it started fine without any problem. is this something that comes and goes? or is my car really okay now?

 

The IAC can stick periodically. If that was the problem, then it may not do it again for a while, or it may start again tomorrow.

 

its your IAC valve. VERY common problem, but the replacements (at least from ford and NAPA) usually are trouble free compared to the stock componant.

i say go ahead and change it, b/c I would hate to be somewhere and then my car not start at all. don't let it go b/c it will only get worse.

 

I would defintely replace as Lee and Jason have said.

Also a tip if you are stuck somewhere and it is acting up. Take a wrench or hard metal object and give the round part of the IAC a few good taps. That usually un-jams it enough to work. I've done this numerous times before I replaced mine. No wrench handy, dont forget you have a tire iron

 

thanks for the tip, im in the process of doing it now. as predicted, the problem only grew worse so its now at the point where it rarely starts without issue. usually you have to hold down the gas to keep the rpms up and then eventually it will start. as of now im waiting to hear from my mechanic about when he can look at it...

or is this easy enough to replace for someone with little knowledge of mustang engines?

 

The IAC is very simple to replace. However, if you dont feel like you can do it then by all means get a professional to replace it.

If you can dig up a pic of a 4.6 engine bay I can show you exactly where it is, and you can see from there if it is something you feel comfortable with changing.

 

Never mind here is a pic I made for someone on another board.




The new one should come with another gasket. All that is involved in swapping it is un bolting the two bolts that hold it on, and disconnecting the tube on the front. Then put the new one in with the new gasket (make sure all of the old gasket is off of the upper intake plenum) and you should be good to go.

 

thanks a lot for the help joker and everyone. im supposed to be taking it in to a mechanic whos a friend of our family tommorow. he works at a ford dealership but hes allowed to do work on his own and use their garage. it works out great because he charges next to nothing for labor...he used to do all the work on my old chevy that i had before i got the mustang. im hoping it all gets taken care of tomorrow.