[Stdyhand]

I have had this car for a little over 6 months. When I got the car it had a lopey sound which could be due to a lot of things. It would die when cold and run rough. Well today I decided to pull the IAC and throttle body to clean it. When I pulled them I found bad carbon deposits. It was very filthy.

After I got them installed and started the car I first noticed the car did not die at all like it normally would. The idle dropped really low during the first 5 seconds and then immediately smoothed out and never done it again after that. The car is running like a dream now. The throttle response is crisp.

The problem is the car is idling at around 1100 RPM. It is staying there, no higher or lower. The idle is good accept the fact it's a little high.

What I'm wondering is if the previous owner may have adjusted the idle higher to compensate for the fact it was running rougher. I've seen this a lot in the past. Rather than look for the cause they just turn the idle up.

What should the car idle at when fully warmed up?

The engine is all stock accept for a CAI which the previous owner put on.

I am going to give it a few miles and if still running good I am going to turn the idle down to whatever it should idle at. Maybe it's just me but 1100 seems rather high once it is warmed up.

[Isambard]

You need to reset your idle.

Ford Mustang Base Idle Reset

[shamrock81887]

Mine is like 625ish cold or warm

[shamrock81887]

Mine hangs for a sec a 1000 then drops to 625 its prolly hangin a bit due to dirty salt n pepper shakers

[Stdyhand]

Thx for the link. I did remove the TPS when I cleaned the throttle body so I'll have to get that voltage set right. I plan on doing this first thing in the morning.

650ish is about what I was thinking but I've never seen this car idle that low before. In fact I don't think it has ever dropped below 800 when fully warmed up, unless it was about to die.


Oh one more question. When I took the throttle body off I saw inside the upper intake and I noticed some moisture in there. I don't know if it's coolant or oil. There was also a lot of black grease inside.

What do you suppose the moisture is from?

Is there a coolant passage that goes through these intakes anywhere?

[fogged306]

Moisture could be oil getting sucked in from the PCV or gas if you are running a little rich. TPS voltage should be fine unless you're getting a code for it. The computer re-learns the voltage with the plate closed every time you turn on the ignition. As long as it's between .5 and 1.19 at idle you're good. Mine is at .55 at idle and I have no issues with idle at all.

Target idle is 672 for these cars. (factory tachs are never close on these cars so if you're in that ballpark, you're probably fine) Check your idle screw and see where it's at if you're hanging that high. Back the screw out all the way, then screw it in until it just touches the stop, and then go one full turn, that should be the correct location for the set screw. Then i would do a base idle reset and let the computer re-learn everything.

[Stdyhand]

I am still working on it. I set the idle to around 650ish rpm and set my TPS sensor voltage to .99 and tightened it back down.

However, the car is still surging. The RPM goes up and then down and repeats this non sto-p. I'm wondering if maybe the EGR needs cleaned or replaced.

I already cleaned my MAF so i'm certain that is't causing the surging.

[fogged306]

If you're getting surging it could be a whole mess of things. I went though surging issues with my car and swapped everything. It ended up being my distributor, but it could be caused by a lot of different things. Any codes stored in the computer?