My engine sounds like it could be missing. the problem usually occurs when the engine is cold but not always. Sometimes it will work fine sometimes it will miss badly and at other times the problem will be small.
Could this be a spark plug wire problem? I've had the plugs replaced but that was back in April. I've never had this problem with any other vehicle so I'm at a total loss.

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1998 F150 XLT, extended cab 3 door,Pacific Green, towing package, 4.6L V8, 3.55 LS,

Performance Mods
SUPERCHIP, K&N FIPK, Dual Exhaust (18" glasspack), Bosh Platinum +4 spark plugs

Apearance Mods
Lund deflector, Profile Windstream side window air deflectors, Prostripe silver multistripe, Diamond Plate Toolbox, Diamond Blue(HID) simulator Fog Lights, High output headlights (80watt low/ 100watt high)

Electronic Mods
Whistler Radar Dectector, Uniden Police Scanner, 29WX-ST Cobra CB Radio, with a Texas Star 100watt modulator and a Wilson 2000 Trucker antenna. A Clarion Security System with Keyless Entry,

Audio Mods
Kenwood KDC-6011 CD player/changer control head unit.
JL 10" sub-woofer
Fultron "Depth Charge" amp 200w max.
4, TR570-CX JL Audio Coaxial Speakers (factory location)

Come see my truck and my grandfather's truck at http://www.geocities.com/vienna/strasse/1992

 

Might check the throttle position sensor if it only misses or hesitates under throttle. If it misses at idle, check the egr valve and/or other emission related components. Your ignition module could be on the blink. It could be plug wires or plugs even though they were recently replaced. Maybe the tech who replaced them didn't get a plug cap on all the way and over time it has loosened off the plug. Could be a number of things. Bad thing is that if it isn't throwing a code, the Tech II or whatever diagnostic machine the dealers will use will not likely reveal much without some effort on their part, which they typically will not do.

Good luck and let us know what you find out.

 

The first time that it happened badly the check engine light came on and stayed on. I reset the computer and it hasn't come back on again. It feels like it is just one cylinder. All of the others are hitting just fine.

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1998 F150 XLT, extended cab 3 door,Pacific Green, towing package, 4.6L V8, 3.55 LS,

Performance Mods
SUPERCHIP, K&N FIPK, Dual Exhaust (18" glasspack), Bosh Platinum +4 spark plugs

Apearance Mods
Lund deflector, Profile Windstream side window air deflectors, Prostripe silver multistripe, Diamond Plate Toolbox, Diamond Blue(HID) simulator Fog Lights, High output headlights (80watt low/ 100watt high)

Electronic Mods
Whistler Radar Dectector, Uniden Police Scanner, 29WX-ST Cobra CB Radio, with a Texas Star 100watt modulator and a Wilson 2000 Trucker antenna. A Clarion Security System with Keyless Entry,

Audio Mods
Kenwood KDC-6011 CD player/changer control head unit.
JL 10" sub-woofer
Fultron "Depth Charge" amp 200w max.
4, TR570-CX JL Audio Coaxial Speakers (factory location)

Come see my truck and my grandfather's truck at http://www.geocities.com/vienna/strasse/1992

 

Just wondering if you have a high output alt. to power all those electric mods. Lack
of power to the ignition could cause a miss,couldn't it? Somebody jump in and tell me I'm wrong or right ......Not sure, just a guess.......98

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98 F-150 4.6 Litre XLT2wd Ext. cab
prarie tan/tan int.
K/N gen.II fipk
custom dual exh/gibson rectangle tips/rear exiting.
color matched snuglid
Superchip!!!
Westin nerfs blk .powdercoat
Clear front corners
Cobra 75WXST cb w/weather alert
Kenwood cd w/Radio Shack speakers,don't laugh it sounds pretty good
On the way/wheels,tires,air dam, etc..etc.......
doin the monochromatic boogie
on the front end.Billet grilles on order
Hoping for deliverance from door crack hell.

 

This is just my personal opinion and experience, but I have never had very good luck with those Bosch platinum 4+ plugs. To me they are a huge rip off. Even with 4 indexes, the plugs still only fire on one of them. They don't index the engine as they are advertised to do at all. I put a set in a new model Silverado truck and the truck lost power and actually developed a rough idle. I would change to a good copper core plug like Autolite or NGK. Copper core plugs conduct better than platinum (even in electronics). Copper or sometimes even gold is used on electronic circuit boards due to its highly conductive properties. The only benefit platinum gives is a longer plug life, but that is because it doesn't conduct as well so the conductor is not worn out as quickly.

MSD, Crane, Jet, Jacobs, etc. all recommend high performance "copper core" plugs to be used with their performance electrical products.

I would change out the plugs to a good copper core plug and change the plug wires to a good carbon element at least 8mm dia. I would also do the things I mentioned earlier and I would also do quick things that are frequently overlooked like cleaning the MAF sensor and such.

Keep us posted.

 

If the check enigne light came on, it registered a code. I'm not sure if it was stored or not. If it comes on again, get the code read.

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2000 F150 XLT 4x4 Short Bed. Amazon Green, 5.4L, SuperCab, ORP, Tow Package, Sliding Rear Window, Electronic Shift, Keyless Entry, LT265-70-17 Tires, Clarion Pro Audio, Herculiner Bedliner, Air Silencer Removed.

1994 SVT Mustang Cobra. #1032 of 6009. Black coupe with black leather int., 3.73 rear, Bassani Exhaust, Aluminum D/S, Bridgestone RE-71 255-45-ZR17

My Home Page

 

i have heard that those bosh platinum +4 plugs are for high mileage motors only and that they are real real bad to low mileage and newer motors
I know for sure if u put them on a high compression motor or one running nitrous or a supercharger that you will be sorry
they cause cool looking explosions

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1999 F-150 Supercab Styleside Lariat 5.4L V8 3.55 gears, Rhino Bedliner
lowered 2/3, 18inch Wheels, Navigator Front End, Factory 2tone Red on top of Gold, Metallic Flake Ghost Flames in the gold
Stock CD player, Rockford Fosgate Punch 250a Amplifier, 2 RF Punch DXL 8inch Subwoofers, 2 Kenwood Midranges in the front doors
By Christmas: Euro tail lights, Superchip, 3/5 drop
By my 17th birthday (March 23rd): White Face Guages, HOPEFULLY A SUPERCHARGER PACKAGE


some quick photos
www.geocities.com/thepyromaniackid

 

I'm not shure if this would have caused it, but, I had gotten gas at a place I havn't gotten it before. I ran the gas till I was on fumes and the filled up at the place I normally do. I've been 150 miles and it hasn't acted up once.

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1998 F150 XLT, extended cab 3 door,Pacific Green, towing package, 4.6L V8, 3.55 LS,

Performance Mods
SUPERCHIP, K&N FIPK, Dual Exhaust (18" glasspack), Bosh Platinum +4 spark plugs

Apearance Mods
Lund deflector, Profile Windstream side window air deflectors, Prostripe silver multistripe, Diamond Plate Toolbox, Diamond Blue(HID) simulator Fog Lights, High output headlights (80watt low/ 100watt high)

Electronic Mods
Whistler Radar Dectector, Uniden Police Scanner, 29WX-ST Cobra CB Radio, with a Texas Star 100watt modulator and a Wilson 2000 Trucker antenna. A Clarion Security System with Keyless Entry,

Audio Mods
Kenwood KDC-6011 CD player/changer control head unit.
JL 10" sub-woofer
Fultron "Depth Charge" amp 200w max.
4, TR570-CX JL Audio Coaxial Speakers (factory location)

Come see my truck and my grandfather's truck at http://www.geocities.com/vienna/strasse/1992

 

There ya have it. It would amaze you just how much crappy gas is out there being sold every day now. They are adding more and more oxygenates and crap to keep the air clean and the vehicles that use it have lowered life expectancies.

 

I hope that, that is what it is. If it is I'm sure glad I didn't run out and spend hundreds of dollars trying to find a problem that may not be there.

 

Day 5 and 200 miles after the new gas. Still no problems.