Hey all, well I've tried cranking the beast w/out using any gas. Had to vilently threaten my right foot!! Yes, it's a habit because the beast cranked right up NO, I don't have a ruff idle. My truck runns smoooth (& sounds grrrreat) I will be working on that foot to gas problem!!! You all do realize that this "foot" has a real serious case of leadfootitist??!!

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97F150 XLT SC 4x4 Flairside 4.6 V8 5sp Dk Toreador Red, 3.55LS
ARE tonneau cover, p255/70rx16 tires (came w/235), Superchip
Pioneer CD w/4 Polk Speakers & Clarion APA5240amp, skid plates
bed liner, side window deflectors, reese hitch, K&N air filter
40s-2chamber Flowmaster, Bosch +4 spark plugs, rustproofing

 

Triton46,
The only performance mod to date is a Superchip.

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99 F150 Lariat SC, 5.4, 3.55 LS, Superchipped, Full Window tint, Deep Wedgewood Blue/Gold, Factory Steps/Towing Package, Rear Slider

 

I'll throw my two cents worth in for consideration... Mine idles a little rough as well; I chalk mine up to the "oxygenated" fuel that we are mandated to use here in metropolitan MD. When I purchase fuel in PA, OH or southern VA (out of the mandated areas) it idles fine, plus the fuel mileage improves by about 2 mpg. We used to only be forced to use "oxygenated" fuel during the winter months, now it is year 'round. They (the government) say that oxygenated fuel lowers the carbon monoxide output from the tail pipe. What I can't figure out, is if you burn 15% more fuel, doesn't that mean there are 15% more other pollutants being produced? Anyway, check and see if you are being "oxygenated" at the fuel pump...


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'98 F-150 4x4 XLT SC/SB, 4.6L automatic, Torreador red, CD changer, Westin step tubes, K&N and other cool stuff... :-)

 

Hmmm, I was just wondering, what is oxygenated fuel?

I have noticed a slight vibration at idle, but I have just chalked it up to the high compression on the modular engines. Of course I could be wrong.

1999 F150 S/C 5.4lL ORP, Amazon Green --Westin Nerf's , airaid FIPK

 

Dear RR,

Yep, you're right, it was me that recommended using Texaco. And you don't have to use premium to get the good detergent additives, unless of course you;re using a Superchip. Texaco was the only oil company to use teh same level of detergent additives in a grades of gas, before the Feds came in and mandated it. Texaco still has the best additive package, in my humble opinion. It improves idle quality better than any other fuel I've ever used, including Amoco, Sunoco, and all the other brand names that come to mind when thinking of the best gasolines. I'm glad it worked for you too!

Bests,

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Mike Troyer
Performance Products, Inc.
National Distributor of Superchips
(540) 862-9515
Email: mtroyer@compuserve.com

 

Ender11,

Oxygenated fuel, in a nutshell, is what the gasoline companies have been serving up for us over the past years plus an additive package (usually a compound called MTBE)of up to 15%, which is supposed to add additional oxygen molecules to the mix. This allegedly causes fewer emissions from the tailpipe, in this case, carbon monoxide. There are a few documented side effects because of the addition of these types of compounds, particularly rough(er) idle and higher fuel consumption (up to 2 mpg less). Adding these types of compounds to the gasoline also increases its volatility which contributes to a much shorter shelf life (in gas cans, fuel tanks, etc.). The fuel can become stale in a relatively short period of time; a matter of months to be exact. But the EPA in its infinite wisdom mandates that these compounds be added in metropolitan areas with high ozone/carbonmonoxide levels.

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'98 F-150 4x4 XLT SC/SB, 4.6L automatic, Dk. Toreador red, CD changer, Westin step tubes, Gibson Swept Side, K&N and other cool stuff... :-)

 

I too have had problems with a rough idle. I had been purchasing the 89 octane fuels, never giving it much thought trying to get "the good stuff" until I read how they got the higher octane....10% grain alcohol. Nice. I went back to 87 octane (non alc.) and now my idle is fine. Live and learn I guess.

 

Looks like I've got a case of the "rough idle", too. My 4.6 vibrates periodically while waiting at red lights.

Thinking it might be the transmission (ya never know), yesterday I did a little experiment. With the transmission in park, I gave it a steady pedal, and noticed that it starts vibrating big time between 1600 and 2000rpms. Below or above those numbers, no problem.

What about motor mounts? Has Ford had any problems with them?

I'm due for my first post-purchase service visit. This will likely be the only item I have for the dealer to look at. I'll keep you posted on the outcome.

 

TexasDude,
Thats exactly what my 4.6 does. A really strong vibration between around 1600 to 2000. Ever since I noticed that vibration in park, I have felt it whilst driving as the engine passes through that range, mostly when letting off the gas to slow down . It kinda jiggles as it passes through that range. Very annoying! And at idle it almost feels like it misses every couple of seconds. I'd like to hear what your dealer has to say. Let us know!
Sykes

 

I have a 1997 4.2 V-6 that had the same or a similar problem. I went 9 rounds (six months) with my dealer until they finally did all the diagnostic tests possible. The cause of the rough idle was the heated oxygen sensors (HO2S). Once they replaced both sensors, the idle smoothed out. Haven't had a problem for a year now.

 

I was just talking to one of the mechanics at work today and he suggested that many of the newer vehicles built today idle a little leaner than they used to due to stricter emission standards. I described the idle problem to him and he said it was probably a "lean miss" meaning there is so little fuel getting into the chamber that it actually misses occasionally. Anyone have any thoughts on this? Any suggestions on how this could be fixed?

 

I also have the rough idle on my '97 5.4. It seems to be mostly at the redlights. What is the cost of the O2 sensor? I am out of warranty.

 

Vol Fan: How many miles do you have on that 97?? I just changed out my spark plugs. The truck ran fine but when I pulled the plugs I discovered that two were in fact bad and this would have lead to the truck running ruff real soon. At the time I had 43k on the ford plugs. (and they are supposed to be 100k plugs, ha!!) Let us know if you check them.

------------------
97F150 XLT SC 4x4 Flairside 4.6 V8 5sp Dk Toreador Red, 3.55LS
ARE tonneau cover, p255/70rx16 tires (came w/235), Superchip
Pioneer CD w/4 Polk Speakers & Clarion APA5240amp, skid plates
bed liner, side window deflectors, reese hitch, K&N air filter
40s-2chamber Flowmaster, Bosch +4 spark plugs, rustproofing
Better Built Stainless nerf bars

 

The truck has 60,000 miles on it, I have only owned the truck for about 9 months, got a great deal on it because of the miles, I looked at the sensors, they don't look that bad to change, I would guess tht the plugs are another story. The rough idle is very sporadic, but I have noticed that the truck runs rough at highway speeds sometimes also, no check engine light.

 

Further up the string, Mike Troyer suggested Texaco as the best fuel in general and specifically to at least help with the rough idle complaint.

Tried it yesterday, and it was nothing short of amazing. I have a 99 Lightning with less than 2K miles, so hopefully no mechanical problems yet in this area. but had a really rough idle condition.

From the get go on the tank of Texaco, the rough idle disappeared.

Might want to try it.

Thanks, again, Mike.

Bill Murray

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Bill Murray
60 going on 17 w/my:
99.5 White Lightning
Bone Stock for now.
Stay tuned.

[This message has been edited by Bill Murray (edited 07-10-1999).]