[Deannostang]

I was just looking through my '98 GT's owners manual (will wonders never cease) and noticed something very odd when Ford made reference to inspecting and replacing single plugs. They state that the "suffixes" on the plugs must match properly for each cylinder and any inspected plug should always be put back in the same hole. Here is how they put it: Cylinders 1, 2, 3 & 4 have a plug suffix of "PG" and cylinders 5, 6, 7 & 8 have a plug suffix of "P". All I can say to that is... WTF?! I have never really ever heard of such a thing with a set of plugs. Does that essentially mean that the "PG" suffixed plugs have a different spec than the "P" suffixed plugs? In that case you must need four of each variety to properly do a plug change. Again.....WTF?! I can't really believe that every aftermarket mfg of plugs out there sells two different plugs for the same engine to be used for a single tune-up?!

I wish someone with extensive Ford knowledge would chime in here and set the record straight. Last summer I installed new NGK "V" plugs that run very well but I did notice the engine idled even smoother at rest with its original Motorcraft platinum plugs. Could this strange suffix situation have something to do with this? It just seems very odd to me the way Ford explains its plugs for the 4.6L 2V. Also, does anyone have any good recommendations for new ignition wires on a '98 GT? Thanks in advance for any help with these matters.

[qwkstang97]

The PG and P on the stock plugs are part numbers for the assembly line they really dont mean anything other than what side of the line they go to.

As for wires I use the FRPP wires. MSD makes them and they are relatively cheap.

[The Greek]

There is a reason that there is two different plugs on your engine. This engine uses coil packs instead of a distributor. One bank fires the plugs from the plug electrode (center electrode) to the ground (side) electrode. The other bank of the engine fires the plug in reverse from the ground electrode to the center electrode. This is why there are two different plugs. If you want to change plugs go with double platiunum plugs, that is what Ford is using on the bank that is firing from ground to the center electrode. You may ask why they didn't use the same plugs all the way around? The answer is simple, economics. I hope this answers the question. All the best,--------Chuck

[Stangman98]

Well now that is interesting. I have never heard that nor have I seen anyone run two different plugs on a Mod Motor. I don't think many people even run the APP764 plug either (that is the Autolite Double Platinum)
I personally run just straight 764 Autolites with absolutly no issues in the last 5 years. To me all DP are good for is gas mileage and not many of us have these cars for gas mileage.