I'm new to the site and I have a few questions. I have a 97 f150 with a 4.6 lately when i start it it idles at around 500. I know this is low because it useto have a much stronger idle. What could be the issue?

 

Yeah Ive had the same kind of prob with my 97 expy but I just bought it but every once in awhile mine has a rough idle but mine if over due a full tune up I'm hoping that will fix it

 

it doesn't have any troubble idling at 500 untill it is coming back down from accelerating it sounds like it may stall

 

My f-150 4.6 is actually stalling pulling into a parking lot or to a set of lights rmps g down to 500 on idle and drop to diddly when i brake.Wheres the idle screw on these new fangled things.(only joking)what is it ,how do i fix

 

All 3 of you - are there any stored codes? If not, the most likely problem is the IAC valve - except the 2004 if it's a NBS, that one has an electronic throttle.

 

I have a 2004 F150 with flucuating idle. It has an electronic throttle. What can I do about the idle problem?

This is the code on my CodeKey.

Standard DTCs (ISO 15031-6/SAE J2012): Idle Air Control System RPM Lower Than Expected

Thanks,

David

 

Clean your MAF and throttle bodies.

 

Cool, thanks for the tip. Can you explain what the MAF is for me?

Thank you!

David

 

http://www.fordf150.net/howto/clean-...low-sensor.php

 

Forgot the big one! Clean your IAC as well.

 

A 2004 with electronic throttle doesn't HAVE an IAC. The code is referring to a problem in the electronic throttle system somewhere.

 

I wasn't replying to him as I know nothing about NBS trucks. This is the 97-03 section.

 

There are TWO different systems being ask about in this thread.
This forum is for 97 to 2003 not 2004 and later trucks.
97-03:
Iac in not open the required amount as controlled by the computer.
This will cause poor cold starts, low idle and stalling.
It is either stuck closed, has an open winding, connector issue and/or sludge/dirt built up at the throttle blade area.
.
04 and later is electronic control and should have CAN codes associated.
In many cases you cannot work on it without prior experience or a working knowledge.
This system is engineered to be as safe from run-away as possible with software and special sub-systems. If you make a mistake in working on it you will just have more problems you can't handle.

 

Where is the IAC? How do I clean/check it? I only have trouble with inital cold start idle. Mileage is down some - avg. 14.5mpg

Thanx - Dean