Hello FTE ! have a question, found a few leaking vacuumm lines and fixed those as well as cleaned throttle body with some throttle plate cleaner...the stumble is gone out of my idle, but my idle seems higher now. i dont have a tac in my truck...
the truck is a 96 f150 4.9 5speed short box...
thanks
aaron

 

Pull the IAC and clean it with O2 safe cleaner. Make sure the spool is free and leave it to dry for about 10 minutes before reinstall. I always set the base idle on a warm engine with AC off then plug the IAC connector in. Seems to help.

 

reset computer after you clean the iac.

 

You probably unintentionaly got crude that washed into the IAC from your cleaning of the throttle plates, so I agree with all the above statements.

 

Thank you for the replies ! I will try that tonight ....Thanks again

 

I have a question regarding the cleaning of the throttlebody/IAC. What is the best cleaner to use? Obviously you cant just use carb cleaner. I am a Ford convert meaning I was a hard-core Chevy man until I bought my first Ford a few years ago and I dont own any GM vehicles anymore. I have had Fords exclusively with the exception of my wife wanting a GMC Envoy......junk. Anyway, I appreciate your experience and guidance.

Dale

 

You have to be very careful when cleaning a throttle body, technically you're not suppose to clean them.

If you completely wash out the inside of them by going nuts, you wash the special film off the bore where the butterflies are and you will have a high-idle problem because too much air is able to go by the blades.

The factory puts a sticker on there telling you not to clean it.

 

I was schooled on mostly GM products. You could use just about anything to clean them. Is there a safe and effective way to go about cleaning the Ford induction systems without damage? I think that my IAC needs cleaning as it idle surges when first started, I just got this truck in question a few weeks ago and its been super cold here. When I first start the truck it idles high for a few seconds and then normal then rises again. It does this a few times before leveling out to a normal idle. The truck runs great overall other than the first start idle surge. After the truck warms up it will start and idle normally. Thanks for the advice.

 

It's suppose to idle high at first startup then come down to a normal idle after a moment.

You can take the IAC off and clean it and re-install it with a new gasket. I would remove the neg batt terminal and clear the computer so it can re-learn its strategies.


You can take the TB off and use a toothbrush and lightly clean the carbon off the back of the bores but don't go nuts and try to get it all off and have it clean as a whistle.

 

Thanks Stang. I may just take the IAC off and do a visual inspection to see how much build up if any is on there. The same with the TB. 'Preciate the info.


Dale

 

Take the two intake ducts off the front of the TB and use your hand to open the throttle blades and look inside with a flashlight.

The carbon on the back of the TB doesn't usually cause a problem...so it doesn't really need to be cleaned. The IAC is what causes a problem because it's how the computer controls the idle and sometimes it will get stuck or gummed up.

 

Ok I tried with the cleaning again. Still High idle. So i went to FORD and bought a new IAC. Put it on ...no change????? Still HIgh. ? Could i have gotten something into the throttle body. I have a check engine light on. High Idle Circuit Code?

 

Did you set the base idle with a warm engine? The high idle can be caused by vacuum leaks or the idle being set too high by the screw. Go over every hose with a fine toothed comb then with the IAC disconnected on a warm engine, turn down the idle screw until the RPM is at the sticker spec. If you can't turn it down using the screw, then you still have a vacuum leak.

 

Fixed problem with fluctuating idle on start up mine other day by accident. Went to start it up and died right after starting, acted like battery was dead so I messed with cables and got it going again, started it up and turned on headlights, bam it went dead again, so I got out battery terminal cleaner and cleaned posts and cables, runs perfect now, rock solid idle. No idea how much I've spent in past trying to fix this problem, figures it was something stupid simple.