surging idle.. help

[SLiM JiM 156]

ok well it all started about 3 weeks ago, i took my car down to get it painted and when i started it up to take it there the idle sounded like i had a big cam. I turned it off and looked around and didnt see anything so i started it up and it was fine. I got the car back and now it surges all the time and sometimes i will be driving and push in the clutch to come to a stop and the car will just die! This is really pissing me off. has anyone ever had this happen? Thanks

Jim

 

[StangLou]

Couple of questions for you.
1# Does it surge on you when you slam on the gas, or can you punch it and it just sit there like its not moving.
2# Does it do this all the time or does it stop after its warmed up?

If #1, you probably have a bad tps sensor. You can get one at most good auto stores and its only a 2 screw job I think it is. Granted Ford uses massive lock tite on their tps screws but its still doable.

If #2. Your IAC could be going. Some people will recommend cleaning it. I dont, it will only do this again in a month or so. Just buy you another one from autozone ro napa. They are about 60 bucks. Another 2 screw job.

Best of luck man

 

[SLiM JiM 156]

there is no surge at all when i step on the gas, Sometimes when im driving though i will keep it at a constant speed and it will feel like the car is jerking back and forth as well. Ahhh i just want to get this fixed.

ill go buy a tps sensor and see if that does the trick

 

[Go HoTO!]

Do you have an aftermarket MAF?

 

[SLiM JiM 156]

also it doesnt surge ALL the time, but when it does it will jump from about 600-1000 down to 300 up to 700 then sometimes it will just die.

Also it doesnt matter if it is warm or cold, it does it all the time

 

[SLiM JiM 156]

Do you have an aftermarket MAF?

yes, i have a lightning mass air.

Thanks for the help guys

 

[00VERT GT]

http://forums.stangnet.com/showthread.php?t=435493

 

[mnbf]

Fixed... for me anyways

Well i had this roblem... my car would idle good cold but when i warmed it up it would surge from 450-900 RPM so i looked at some posts here and i went out and turned my idle screw ( on stock TB ) and turned the car on and it idled a little hight so i just layed around with the screw and got it set just right. seems to work for now ... hope it doesnt come back.. the idle screw was on the back of the TB .... if anyone wants a pic let me know... just a side note ... if idle doesnt drop like you would like it you might want to try the the pipe cap mod .. where you put the pipe cap ( with a hole drillied in it)in the hose that goes to the IAC... well thats what i think...

 

[StangLou]

I WANT A PIC!!!!!!!!!!!!!!

My idle is pretty low and it annoys me. It sits at like 600 and I want it at like 800 at least so I can hear something from my exhaust .

On topic .... Sounds like your IAC to me man, save your money from the tps and get a new IAC. Could be your MAM to

 

[SLiM JiM 156]

ok now this is really pissing me off, I tried messing with the idle screw and it turned it up to about 900, well now its at the point where i start the car, it will run perfectly at 900 rpm with absolutley no surging, then about 30-minute later it will start suring to 600-1300-600-1300-400-1200 then it will almost die then go back up to 1300 then it will just flat out die, it does this everytime i start this..

i had my car painted and the place pressure washed my engine bay so i was thinking maybe something got fked up.

 

[Go HoTO!]

Look man, you can not mess with the idle like that just because you like the sound of the exhaust!!! The idle setting is a very technical setting for the car and is tied in to many things. You idle is "hunting" because it is confused. This normally happens when the base idle is set too low, so you most likely have two separate problems.

First, you need to reset the base idle. To do this, remove the wire connection on the IAC. Then start the engine. If the base idle is set properly, the car will run without touching the pedal and will almost seems like it will die. Turn the idle screw back down to lower the idle speed until this happens.

Turn the car off and re-connect the wire harness to the IAC.

Is your after-market MAF been dyno tuned? Are you sure that you need it?

The next thing you may want to do is to replace the TPS. If it were me, I would spend the $24 on one as the money really would not concern me and I don't have the time to go fishing for multiple problems. If you wish, replace the TPS.

Disconnect the battery either way to reset the computer. Keep is disconnected for at least 30 minutes to ensure that all the memory is gone. Reconnect and restart the car. Let is idle until the engine warms up. Then, turn on your accessories for a while.

You need to drive the car for 200 - 300 miles before the car has remapped all the fuel curves. Give it a few days. So, don't get too excited at first if things don't seem right. Give it sometime and then stop messing with the idle setting.

 

[awwyea]

ok now this is really pissing me off, I tried messing with the idle screw and it turned it up to about 900, well now its at the point where i start the car, it will run perfectly at 900 rpm with absolutley no surging, then about 30-minute later it will start suring to 600-1300-600-1300-400-1200 then it will almost die then go back up to 1300 then it will just flat out die, it does this everytime i start this..

i had my car painted and the place pressure washed my engine bay so i was thinking maybe something got fked up.

Chances are your plug wire caps are full of water. You should pull each one out and dry it off with compressed air if you have it or, let it air dry all day or night.

 

[StangLou]

Yep since they presure washed your engine, they probably fudged something electrical up. coil packs might need to be replaced, could be the connecting plug that goes on top of your mam, or even your alt could be messed up now.
GoHoTo I was just kidding when i said that. I have a full exhaust lol, I hear plent from it at idle , even if it is just at 600 it still sound My only complaint about it being that low is every now and then it will stumble. its not that noticable, but it does happen. Its been dyno tuned, ect... just something that happenes when you go with L/T's.

 

[SLiM JiM 156]

Chances are your plug wire caps are full of water. You should pull each one out and dry it off with compressed air if you have it or, let it air dry all day or night.

i pulled one of the plug boots and the whole thing was an orange/rust color like its been sitting there for a long time, im going to go try and change all the plugs later today cause it needs it anyways

 

[StangVert00]

Mine sometimes surges when I place it in Reverse. (Auto) I'm glad I still have my foot on the brake!

StangVert00