I'm bringing this up again, becuase after having read all the posts that came up on my searches, i'm stillunclear as how to resolve my problem.

This was discussed as a result sometimes from having used a K&N Filter, which i did use for about 10k.

Recently the truck has started doing that dip to 400rpms, surge to 1100 rpms, then back to it's 700rpm idle.
-Stock 4.6
-Ford OEM Air filter
-only happens when engine is warm, regardless of ambient temp
-only when at a complete stop.

Any info on what to check and repair/replace would be appreciated, the truck is almost stalling now. This has all happened within the last two weeks.

TIA
Bambino

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Bambino Photo Gallery
1999 reg cab/short box/ORP/Silver on Dk Graphite - 3.55; 4.6l 5sp; Factory Tonneau; 40 chan CB/Maxrad Antenna; Kicker amp'd sub tubes; Rockford Fosgate components up front; Custom Exhaust; Mobil 1 5w30/Motorcraft FL820s; Amsoil Series 2k in the driveline.

 

Mine does that once in a while i will be checking in to see if anyone has an answer!!

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1997 F-150 XLT 4.6 shortbed REGULAR CAB, FLARESIDE CLEARCOAT GREEN 5-SPEED. WESTIN NERF BARS, POWER EVERYTHING,BUG SHIELD, EX-TANG SOFT COVER, BED LINER(FORD).

Better 1/2 : 92 Red T-Bird V-6 3.8. maint.free 113,500 miles

 

Mine did that and I changed the plugs 2 weeks ago. Hasn't happened since. Hope this helps.

CJ

 

Maybe not even close (but it's a Ford), but my 86 Mustang GT used to do that about twice a year. I would just reset the computer, and it would stop for like 6 months..... I know that's not a resolution for your problem, but maybe something to try? At least that would eliminate that as the problem!

 

Hey there-
Yep, it's a bit odd, and the dealer just looked at me like I was crazy when I told 'em. In my case, it happens once a week or so, especially when I put her in reverse and back out slowly. It's almost guaranteed if I don't wait for the idle to settle before I put it in gear. It makes me wonder if the idle air control valve or solinoid has bad contacts, or it's getting bad information from the throttle positioning system. It sure gets me mad, though! I've
actually had to turn the vehicle off a couple of times the surge was so bad (+-400 RPM). Anybody??

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'01 F-150 XLT Supercab 4.6 Auto, 3.55LS, CLIII Tow. Blah Blah Blah
K+N FIPK, 3" Catback w/ Dynomax w/swept side exit

[This message has been edited by palerider (edited 06-28-2001).]

[This message has been edited by palerider (edited 06-28-2001).]

 

I'm looking at the IAC this weekend, I think that that is the best place to start. As stated, i've already cleaned the MAF, and the the intake up to the throttle body.

Prior posts included checking the voltage on the IAC to make sure it was within reason, i'll see if i can do that.
Mainly curious to see if anyone else has this problem licked. It seems like it mainly happens to 4.6's with the 5sp...but it might happen to you guys with auto-magics too.

Bambino

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Bambino Photo Gallery
1999 reg cab/short box/ORP/Silver on Dk Graphite - 3.55; 4.6l 5sp; Factory Tonneau; 40 chan CB/Maxrad Antenna; Kicker amp'd sub tubes; Rockford Fosgate components up front; Custom Exhaust; Mobil 1 5w30/Motorcraft FL820s; Amsoil Series 2k in the driveline.

 

I hjad erratic idle on my '99 5.4L engine. Bought some spray fuel injection/ carb cleaner that was deemed safe for Oxygen sensors and catalytic converter. Removed inlet air tube and sprayed off the idle control passge and plunger. Ran engine for a bit and then repeated procedure. Oil residue and dirt/carbon build up on the plunger and makes it stick. The 5.4L IAC (idle air control) seems fairly difficult to remove and clean, but on the 4.6L engine it may be easier. If that is the case, simply remove and clean. Might want to get a new gasket before removing the IAC though.

 

yup, i think i'm going to work on that IAC this weekend, and check the voltage on it too - i believe i saw somewhere in the haynes manual or a post from jmc about testing the voltage.

I'll post results.
Thanks.

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Bambino Photo Gallery
1999 reg cab/short box/ORP/Silver on Dk Graphite - 3.55; 4.6l 5sp; Factory Tonneau; 40 chan CB/Maxrad Antenna; Kicker amp'd sub tubes; Rockford Fosgate components up front; Custom Exhaust; Mobil 1 5w30/Motorcraft FL820s; Amsoil Series 2k in the driveline.

 

Mine was doing this more and more frequently over the past couple of months and I finally got a "Service Engine Soon" light. I took it in (under waranty) and the dealer reprogramed the PCM. Now it doesn't idle at all! It died 5 time at stoplights this weekend. Obviously it's going back as soon as possible.

 

My 2001 4.6 has done this since it was new. First time was about 250 miles. It now does it about 1 time every two weeks or so. It always seems to be if I shut the engine off when hot and then leave again in about 30 minutes or so. Especialy if I engage reverse and just tap the throttle a bit. The truck sometimes needs to be shut off then restarted, and sometimes the engine will clear up if I put it in Nuetral and jam the throttle for a second. As for checking out the issue, nah. I don't see the point in chassing it down. I know the dealers are all to stupid to fix it, let alone find it. That has been proven to me on many Fords for many years. I leased the truck, so when the next guy buys it, he can worry about it. I don't see the issue as that big of a deal.

Just my .02 cents.

Hope you guys have success in your efforts though.