at 73,000 miles on my 97 4.2L auto i've been experiencing the rough idle/shuddering/dieing while at a stop for the last 5,000 miles (i drive alot, maybe too much). I went out and bought 6 bosch plat 4's. dad put them in last night and today the truck ran as smooth as it did the first day i drove it over 2 years ago. however, he said their wasn't anything wrong w/ the old spark plugs. I'll keep you updated should the problem rear its ugly head again.

he did find a small oil leak in the left valve cover.

 

Last I checked, they didn't make the +4 for our engine. Do you remember the part number?

------------------
Danny
'98 F-150 Std., RC, SB, 4x2, 4.2L, 5-sp, 3.08, AC, speed control,
rear slider.
Mods: Mobil 1 engine oil, Red Line D4-ATF trans fluid,
Edelbrock IAS shocks, 50 Series Flowmaster,
K&N with airbox mod, Perma-Cool electric radiator fan,
Superchip, ASP underdrive pulley

 

Bosch 4469 is the correct +4 for the 4.2L engine. Old plugs may have had worn insulators, i.e. cracked ceramics that allowed grounding and a weak spark. The Autolite Platinum Plus is a better plug than the bosch +4; use APP5144.

 

ponysix8, I had the same problem sitting at a stop light it wanted to die. I bought my truck with low miles and at 14,000 miles and 3 years old I wanted to change spark plugs, I bought and installed them. tried them for a week and took them back. Every one of them were carboned up bad, real bad. I took them back for a full refund and bought the motorcraft platinum plugs and no problems.

------------------
1997 F-150 XL Flareside 4.2, Auto 3.08, K&N Air Filter, Glass Pack Muffler single in dual out, Superchip, Diehard Security Battery, Cragar Rims, Tail Light Modification

 

We've had excellent results with every vehicle we've put the Bosch Platinum +4 spark plug in, and highly recommend them.

The factory manual says the spark plugs are good for 100,000 miles in many FoMoCo vehicles, and yes, they'll fire for that long, but by the time you have 30,000 miles on the V-8's you have already lost anywhere from 8 to as much as 12-13 horsepower from plug "wear".

Glad to hear you've running smooth again, Pony.

------------------
Mike Troyer
Performance Products, Inc.
National Distributor of Superchips
(540) 862-9515
Email: mtroyer@compuserve.com
Performance Products F150Online Superchip ordering system: F150Online Superchip Ordering System
First National F-150 Online Rally Event Organizer

 

I have had the Bosh Plat +4's in my 98 since I bough the SuperChip for it. I have had no problems with them. I recommned them to anyone looking to replace their plugs. I found a smoother idle and better performance with the new plugs.

Randy

 

well, that didn't cure my problem. truck died twice this weekend while sitting in drive with low idle.
sparkplugs are staying. something else is wrong. bad gas this summer??

 

forgive me if this ends up being a stupid answer, but my daughters 92 dodge caravan was doing the exact same thing,,,i thought it was bad gas, wrong gas, etc..took it in tpo pep boys and they replaced an idler motor( i think that is what he called it ) she hasnt had the problem since,, now not ANYTHING about engines at all, i do not even know if the 4.2 has an idler motor..

------------------
97 f150 xlt SuperCab 4.2L, Auto, K&N Air Filter,Captain's Chairs, Magnum Bug Deflector, GTS Headlite Covers, AVS Slotted Tailite Covers, AVS Window Deflectors, Ford Bedliner, Ford Blanket ( Thanks Raoul )


"Just FORD It"

 

Pony what about your fuel filter have checked that yet.

 

ponysix8,

My 4.2L also dies or runs really rough occasionally at stop lights, usually after a long 80 mph run down the interstate. Keep us posted if you find the problem. Mine is a 97 with over 67,000 miles.

 

Why does the manual say to use two diffrent type plugs? One type for the left and one for the right? Ive heard one side burns hotter. Does this matter when replacing them with aftermarket plugs?

------------------
1999 F150 4x4 sport package,4.2 V6
planning lots of mods

 

fuel filter was replaced a couple of months ago. i know its not computer related b/c that has already been checked.

 

Hey Ponysix8,

I had the exact problem about a month ago.It ran real rough when parked or sitting at a light..I would have to give it gas and hold the brake to keep it from dying...

The problem was a vacuum leak..I took it to my dealership and $50 later the problem was fixed...Please have it checked for a vacuum leak, I would almost guarantee that's the problem if you have a clean filter..

------------------
1999 F-150 5.4 Lariat 4x4 w/ORP 3.73 gears

Current Performance Mods:

*MAGNACHARGER Supercharger
*Superchip
*K&N FIPK
*Edlebrock 75mm Throttle Body
*Granatelli MAF
*JBA Headers
*Flowmaster 40 DeltaFlow with duals @ 45Degree angle

Mods Soon to Be:

*Pro-M 80mm calibrated MAF+Filter
*Motorsport 24lb Injectors
*Re-Flashed Superchip

Wish List:

*Custom Head and Cam Job
*Upgraded Ignition
*Possibly a shot of N2O
*4.10 Gears
*Forged Pistons and rods

 

My wife had the same problem with her Escort. Rough idle and then it would quit. We took it to the dealer and they put in PCV.No problems sence.

98 F-150 4.2,Supercab,longbed,Pacific green
Leer cap
bug shield
Mobil 1