Car dies for some reson after WOT.

[hotmustang331]

(^typo..reason) Yea, at the track it did it TWICE, when I push in the clutch the rpms drop down all the way to 200-300RPM and float for a sec then the car dies. It would have did it again, but I reved it to keep it alive. Then yesterday I went WOT 2-4th. Just into 4th and let off, pushed in the clutch and slowed down to the speed limit and the car dies AGAIN. Pop the clutch and like always its fine. Then today after I went to a big car show thing in Austin, left there and was cruizing at 65ish, red light...push in the clutch and there go the RPMs again down to 400-500 ish but I reved before it died....came to about a stop and it tried to die again and I had to rev it. Im thinking its my IAC valve ....I bet its getting dirty. Any suggestions that may point to something else?

 

[40th GT]

If you're keeping up with the preventative maintanence stuff, then yeah, it's most likey the IAC.

 

[csledd]

Check that stupid IAC, I hate it. I think mines going bad too because that also happened to me once. I had just installed my gears and had just about finished doing the whole warming up and cooling down phase and got on it for the FIRST time and it did that, I was just like "oh ****". You might remember there's a humming noise coming from my engine, I'm guessing that's cuz of the IAC too, I just haven't got around to repalcing it :\

 

[spdfrkaby]

Also check the MAF sensor. Need a special tool to get to it and use electrical wire cleaner on it.

 

[mrvax]

It sounds like the IAC to me also. If a new one doesn't fix this problem, try the recommended fix for the typical hanging idle problem that has been posted here.

 

[hotmustang331]

Thanks guys, I think I may buy one. But I have been noticing lately that the car doesnt "hang" after pushing in the clutch, 9 out of 10 times it just dropps down immediatly to 900ish RPMs...and sometimes it does the above and dies. I may buy that plate Mrvax if the new IAC makes the rpms float again. I will also check the MAF as a last resort...looked darn clean last time I checked

Csledd your still dealing with that loud noise? I thought you fixed that after that guy said his crown vic or whatever's IAC made the same noise.

 

[csledd]

Csledd your still dealing with that loud noise? I thought you fixed that after that guy said his crown vic or whatever's IAC made the same noise.

yeah.. I never cleaned the IAC or replaced it, I've just been lazy lol

 

[hotmustang331]

Has the noise and or idle problems been getting worse? Mine has seemed to come on pretty quick and I dont want the car to keep getting worse at this same rate. IAC is like $50, so i may have to go get one.

 

[csledd]

nope, seems to be staying constant.. but then again ive just got to the point where i drown it out

 

[timeless2]

Geez, HM; a faulty IAC on your '04? How many miles do you have? I hope mine doesn't crap out soon.

 

[hotmustang331]

I have 30,900ish. I know, alot of miles for an 04. this also seemed to happen only after the cams and tune....so maybe its related. However these IACs seems to sometimes go out when other mods are added at the same time and people dont think its that because it was working fine before...and when they replace it the problem is solved. Thats why I am not sure because the cams could very well be causing this.....just trying to see some more symptoms of the IAC going bad. (ie dieing after WOT runs) Thanks

 

[csledd]

hey the same thing happened to me, after I put my tb and plenum on that noise popped up directly after o:

 

[hotmustang331]

Well your accufab plenum is smooth, I wonder if its leaking around the edges.

See im starting to think that when you increase airflow it reaches the flow limit of the iac sooner and when its already partially dirty the increase just pushes it over the edge....just a thought though.

 

[csledd]

are you saying replacing it may not help? or just that it needs to be cleaned

 

[hotmustang331]

Cleaning is alot cheaper. Try that first lol...I think I will pull mine tommorow and see what she looks like.

Oh and no im not saying that replacing it wont help, UNLESS its not sealing. What i was saying was that if its already dirty and then you add airflow it may push it into its problem zone....and at that point it needs to be cleaned or replaced to have enough flow to support the engines higher airflow demands at idle. But that is just my thinking since this seems to happen when we add some airflow improving modifications.

 

[timeless2]

HM, when you find out what it is, please post up.

 

[BooWFO]

Ok my.02 make sure everything is tight and in place. Then clean the IAC. I've had the hoses loosen up on me after doing something then driving it hard.

 

[hotmustang331]

Ok, im going out there right now...ill take a pic of before and after I clean it...this is one thing I wont P&P while I have it off.

BTW I just ordered my BBK ceramic coated long tube headers from summit ....$508 shipped, not bad at all. Saved over $30 on shipping costs over other places, because summit only charges $8 for handling, free shipping and tax is included.

 

[hotmustang331]

BEFORE...yes thats my time slip .

AFTER will be up shorty, but i wanted to post this because the thing looks freekin clean...I mean its a little dirty but no like buildup. I am going to try and find some carb cleaner. if I cant them in screwed lol.

 

[timeless2]

BEFORE...yes thats my time slip .

AFTER will be up shorty, but i wanted to post this because the thing looks freekin clean...I mean its a little dirty but no like buildup. I am going to try and find some carb cleaner. if I cant them in screwed lol.

Scary part is; it looks fine from those photos.