jwalk2c

Would like to ask advice on 1st tune up 1997 F150 Lariat, 5.4 with approx. 90,000 miles, has very pronounced misfire in Overdrive and has progressively gotten worse to the point that on any incline must turn off OD or it will shake itself terribly.My scanner reports code P0304 which I understand is cylinder # 4 misfire. I plan to replace all 8 plugs with Motorcraft AGSF-22F-SMF6, which btw is the p/n that Ford website chat person gave me per the VIN 1FTEF17L1VNB81100.And the same chat person gave me coil pack p/n 3W7Z-12029-AA which I think is DG-508 and seems to be available online at various prices with mixed reviews concerning authenticity.This is my first attempt at replacing plugs on these types of engines and coil packs in general. I have watched several youtube videos and will take it slow.I am open to any suggestions and my main questions:1: What is your opinion of replacing all 8 coil packs or just the one on cylinder 4? I am not a fast worker and in light of all the parts that have to be removed to gain access to the coil packs, in my opinion, it would be worth spending $320 (online price, for example, www.fordpartsgiant.com ) on all 8 coil packs and do the job right, if I could depend on getting quality parts. As a comparison, a Brick and mortar dealer retail is $503 which makes the decision to change out all 8 that much more difficult.2: Any recommendations on how to ensure getting genuine OEM coil packs, other than purchasing from a brick and mortar Ford dealer?3: Does that spark plug p/n AGSF-22F-SMF6 seem correct to you guys? As I mentioned I need all the advice I can get.

Thank you

Johnny Walker

raski

Clear the codes and I would swap coil packs with another cylinder and see if the new code issued follows the coil pack in question or stays with the cylinder.
No, I would not change out all coil packs. Only the faulty one for me because I am cheap. Running plugs past their normal change interval is harder on the coils because they must work harder to fire accross a wider gap because the plugs are worn.
You could go to motorcraft.com and double check the plug numbers. Also, I get my parts from rockauto.com. Cheapest prices and they do carry motorcraft.

jwalk2c

Thank you, I did not realize that running plugs past normal change interval was hard on coils.
I did not know about motorcraft.com, I will check the plug number there.
Thanks again
Johnny Walker