Help! Idleing Problem...

[Quijibow_69]

Sometimes when I start my Mustang up, the Tach drops way below 500 RPMs and fluctuates between 1000 RMPs and 500 RPMs and seems like it's gonna stall. The battery also flucuates at this point. Once or twice the car actually stalled on me. Does anyone have any idea what this might be? I have 85000 miles on the car. Also, my car is basically stock, where should it be idling at?

Thanks!

 

[Paul Perreca]

no advice, but cant wait to hear it, my cars doing the exact same thing, to the battery as well, and it actually stalled once or twice - sometimes it actually stalls when im driving like if im at a red light, i gotta keep my foot on the gas alittle to keep the R's up - help us!!!!!!!!
Paul Perreca mines got 110k

 

[blastit116]

got the same problem but it is only at start up.

 

[blwnstang90302]

your problem is a bad idle control motor which is attached to your throttle body. Mine went bad and the symptoms were exactly as you described. They are around 100 bucks for a new one.

 

[Quijibow_69]

Hey blwnstang90302, could you click on this link at let me know if this is what you needed to replace...thanks!

http://secure.50resto.com/product1.cfm?SID=1&Product_ID=269

 

[Curse]

I have the same problem you guys are having. In my case it is not the IAC cleaned it many times then I replaced it, no difference. I thought I have fixed this problem when I did my head swap. I cleaned all the sensors and EGR along with a bunch of other stuff, it stopped doing it after that. Recently it started up again, don't know what else to do.

 

[DMAN302]

Common problem..unfortunately many possible causes. Check for vaccume leaks EVERYWHERE..little lines, big ones, pcv grommet seal. Check the TPS voltage, clean the IAC, even check the timing. Little issues can contribute to where there may be no one answer, or could be as simple as broken vac line. Go over the engine bay..follow every line, I often find a broken one when things like that start.

 

[blwnstang90302]

DMAN, you are correct in checking for vacuum leaks which is also a common cause of this problem but i have also seen many cases where the idle control motor went bad and by replacing it, fixed the problem. For those who are having this idle problem i would first start with checking for common problems such as leaks as dman described, if nothing works replace the motor. this is what i did and the motor was the problem.

 

[bock]

A cheap T.B. can do this....

 

[darthcual]

I agree it sounds like the idle air control iffin i be you i would go to my local bone yard a gank one. This will likely fix the problem.

DC

 

[sweet93hatch]

I recently had the same problem but in reverse. My cars idle would surge and then come back down. I changed the IAC and cleaed the TB and still no dice. My problem ended up being the TPS.

 

[28]

Mine was dirty IAC....Took a while to figure it out though...I think a dirty TB will cause this also....Good luck..

 

[HISSIN50]

i like the info on this thread. also, if not explicitly mentioned, cleaning the 10 pins can really help. all the clean sensors in the world dont help much if their signal is lost in a bad connection.