hi, i'v got a 98 4.2 v6 with 50k only, mostly city driving. never changed my plugs yet. got a check engine light that came on. reads a misfire in cylinder 3. planning to change my plugs. what should i use? read about autolite copper plugs being very good plugs with best deal for your money. should i go for it?

 

Nope, use the factory type Motorcraft platinums. They aren't expensive.

 

the SP-504 Motorcraft Platniums will last the longest and run smoothest, but copper is more conductive so some people run coppers for the performance, but change them almost every month.

but yeah, just go with the SP-504s and gap them .052-.056" - mine are at .054"

 

thanks for the feedback! still confused with what motocraft to buy. some say AGSF34EE, AGSF34FM, SP-504, 22FM, ST500, etc.. what should i use for my 98 4.2 v6? where can i buy them? thanks again!

 

They list this, just look it up, it's not hard ~

Motorcraft Spark Plug - Direct OE Replacement -

Part Number: MISP504Manufacturer Number: SP504

MOTORCRAFT SUPPRESSOR SPARK PLUG, SOLD INDIVIDUALLY -- Delivers maximum voltage to the spark plug while maximizing performance and increases engine life; Resists corrosion and abrasion; Reduces the chance of misfire.

Type: Direct OE Replacement
Availability:In stock

Fits the following 1998 Ford F-150 submodels:

1998:Base; 6 Cyl 4.2L; "GAS, FI, VIN 2"
1998:Base; 6 Cyl 4.2L; "GAS, VIN 2"

That's all they list.

 

ok jbrew, got it! thanks much.

 

I think for all it's worth... I'd stay away from everything else... just stick with Motorcrafts. I've got Autolite Finewires in my truck now and everything is all hunkie-dori with it, but I am going to pull them after 20k and put the SP-504's in.