engine idling problem
 

i was wondering if someone could help me out here, i have a problem with my engine idling up to 1500-2000 rpm's when i am at a stop light or just sitting in neutral, it is mostly when my car is warm that it wants to do this, it has been an on going problem since i first bought the car last year and i recently did a tune up including plugs (bosch platinum), wires (accell street custom fit), cap & rotor (platinum gold) and an oil change with valvoline higher mileage engine oil and it seemed to not want to idle as much as it used to but it is still there, i have been told to replace my oxygen sensors and i have been underneath the car and they look like they have never been done since it first came out of the factory, so i am wondering if anybody else has had this problem and if they have fixed it with the solution i just said (oxygen sensors) i know it would be a good idea to replace the sensors as it is but with $60.00 a piece canadian and with two of them needed, money is kinda tight, so that is why i need to know if this is the problem, thanx for your concern.

Adam,

Welcome to the boards, bro.

If you'll post some information about your car...what year, what model, mods, mileage, etc. we could give you some advice.

Also, you may get a getter response over in the Windsor power forum for this type of discussion. Most of what goes on in here is general discussions about anything and everything...the Windsor Power forum is a dedicated tech. forum for late model V-8 stangs.

You may also want to try the search feature on the board. It works really well. Search for "idle problem" or "rough idle" or something along those lines, and it will pull up previous posts from the forums you chose. It comes in handy when researching problems and saves time.

Once again, welcome aboard...I'm sure you'll find this site to be the best Mustang specific site on the internet with lots of great help, great folks, and great friends.

God bless.

--nathan

SOUNDS LIKE IAC MOTOR TROUBLE TO
ME TRY TAKING IT OFF AND CLEANING
IT WITH CARB CLEANER LET IT DRY
THEN PUT IT BACK ON IF THAT HELPS
THE IAC IS PROBLY BAD.



FLEA

If they are original, the O2 sensors should be changed, and that could solve your problem, but I'd like to know what codes are being generated first.

He's right, the IAC pintle becoming stuck with carbon is the #1 reason for idle froblems on 5.0 FI engines.

Inevitable idle problem
 

Adam:

Try removing and thoroughly cleaning the IAC motor (attached to the TB) first since it's fairly easy - and free. Once the IAC has been re-installed, re-set the on-board computer by disconnecting the negative battery cable for 15 minutes, reconnect it then start the engine and run at idle with all accessories on for 2 minutes; engine off for two minutes, idle with no accessories on for two minutes, engine off for two minutes, then drive normally. The computer should compensate for the new values.

If that has no effect on the idle, you should certainly try to pull codes but you may well have to invest in new oxygen sensors.

I Had the same problem with my 86, it would surge real bad especially when the AC was on. I replace the IAC and EGR and it helped a little. I then replaced the EGR vacum regulator solenoid, (thats what the haynes manual calls it, the dealer calls it some thing else) anyway it cured the surging problem. The dealer was the only one to have it. It's located on the side of the pax shock tower. It's not the side by side TAD/TAB solenoids.