Doug@C&L

Hey guys,

I've been talking with alot of my dealer friends and we are getting quite a few concerns about idle speeds or actually lack there of. If you car drops the idle when coming to a stop, goes down to like 400-500 rpms for a second and then comes back upto 740, then it probalby because of a dirty throttle body.

What happens is oil residue will build up on the throttle plates and the inside of the throttle body bore. Since these cars use the throttle to adjust the idle speed, unlike the previous years using an idle speed controll airbypass, this can cause the throttle plates to stick or even bind.

The easy fix for this, simply get some throttle body cleaner or brake cleaner, NOT CARB CLEANER, and spray it on a cloth wrag and clean your TB. You can do it on the car, just remove the intake hose and push the throttle plate open by hand and wipe around where it contacts the body of the unit. The best way of course is to remove the throttle body and this way you can get to the backside of it too. You dont have to remove the throttle mechanism to do this, just the four bolts around the outside of the unit.

Now this is what a few dealerships have been doing to resolve this issue and I've even found on my personal car. Before you do this though you should always check for the small things first, loose clamps, air leaks, vacuum line going to the pass. valve cover, and any other small visual issues. If you car has run a tune for a while and it just started this recently then the tune isn't the issue.

Just let me know if I can help with any other questions you may have. If need be I can make some photo's showing more about this. Maybe get one of those nice Tacobill write ups

Thanks, Doug.

neil07gt

How about a "sometimes" rough start followed by a high idle like 1100-1200? Instead of a crisp startup, on some mornings I get a rough start (kinda like bad gas) followed by a high idle. Then, it takes about 5 minutes or little more for the idle to eventually settle down to normal.

Scothew

Just to stress on what Doug said.. Dont Use Carb Cleaner.

The throttle body blade has a coating (teflon or similar) to help keep buildup off of it, and the carb cleaner will diminish this coating. Throttle body cleaner is the most prefered chemical to use.

05GT-O.C.D.

This is excellent. I've had this problem for well over a year, but with the WMS intake I've got no way to put the stock airbox on for warranty. Thank you!

05GT-O.C.D.

Also, I've noticed it seems more common during cooler weather. Does anyone know the rationale for this? More dense air?

atomic_il

If the car starts to die after it does the symptoms mentioned, take it to the dealership. that is what mine did and they replaced the TPS's which had gone bad.

05YellowGT

Doug , can you recommend a cleaner. I did a search and found some Valvoline Syn Power , but it says carb, choke and throttle body ...

SoFlaBoss

Doug, Thank you for sharing this.

Doug@C&L

I prefer brake cleaner but any type of electrical cleaner, brake cleaner or throttle body specific cleaner, I wouldn't recommend using a carb and throttle body cleaner.

The reason I prefer Brake cleaner is that it is safe on rubber seals and so forthe where as carb cleaners will eat up O-rings and electrical connectors.

I'm trying to find a cleaner online that I can recommend, give me a few and I'll post one...

Thanks Doug.

ARBO

I heard this was happening more to people that have "oiled" air filters. For what that's worth.

SlamMan02

Everyonce in a while mine does it if I put it in neutral and coast down from around 60mph...If I put it in neutral and cost down from around 40mph or less then it doesnt do it.

Doug@C&L

Here's a link to some throttle body and intake cleaner. Mainly what you are looking for is it to say that it is safe for coated throttle bodies as Scott mentions above and this cleaner even says it lubricates...

http://www.amazon.com/Throttle-Plate...577060-0231257

Thanks, Doug.

awakeinAZ

That makes sense, most of us are running aftermarket CAI's with oil. So, we will be the ones with these issues. Especially a 2005 that has had one for ahwile.

Does Ford oil their FRPP filter?

( All of a sudden, I may be glad I have my stock airbox packed away on a shelf)

G.T

Great write up Doug, i'm sure this will help a few.

remember my idle problems?
in my case however, cleaning the TB didn't quite help.
i had my TB clean and shiny like a mirror, yet my car was still idling like crap.. surging RPMs while idling and sometimes stalling.
2 months later my TB finally threw a DTC and ford replaced it under warranty.. and the problem is history.

i think my next mod will be an oil separator on the PCV line, which would make sure my TB stays relatively clean

superman112

Nice write up Doug... if only you would have had this about a month ago!! Ha ha I had so many problems with mine and the delaership cleaned out my TB AND SO FAR SO GOOD. oh and Doug I'mn having those cams installed next weekend. Am I gonna need a new tune or will I be fine with the Race tune I'm using now? We is AWESOME by the way!

GT John

Did mine yesterday. Car has 20K miles on it. It was dirty in there. some kind of black stuff. Also cleaned the MAF sensor while I was there.
Thanks Doug.

BuzzyStang05

Ditto. Haven't drove it yet, but I'm sure that black gunk wasn't helping. By the way, if you decide to spray the stuff while the TB is still on the car - be careful. Most brake cleaner sprays I have used will easily strip paint and melt plastic. Do what Doug says - spray it on a rag first and wipe or remove the TB from the car completely.

mvon919

I need to check this... I get rough starts too when cold. I've been thinking it's because I gapped my plugs to .032" but this might be worth a shot to check. There's no other problems, so it might not be gapping problem. As said, I'll check my TB and clean it with vodka.

Chilliwack 42

My brother is a mechanic and was reading up on 05+ mustangs. I'm not sure if he read about it or where he got it from, but he said I shouldn't move the butterfly valve of the throttle body by hand because it can mess up the drive by wire system? has anyone heard or can confrim this?

metroplex

Doug: what we need is an OEM-quality oil separator for the PCV vacuum line to prevent engine oil mist from reaching the throttle body. The Steeda separator with the clear polycarb bowl is just an air compressor inline filter (not rated for sub-30F temperatures).