99 Mounty 5.0L Replaced spark plugs - Runs Poor

[RickMar]

Thank you for taking the time to read this post.
I replaced the spark plugs in my 99 Mountaineer 5.0L with 205,000+ miles.
Believe it or not the Mounty was running just a little bit ruff at idle. I had plenty of power and smooth acceleration. Now and then, just to clear it out (I could wind it up to 110 MPH) on the highway, with well over 100,00 miles on the spark plugs. I was amazed of how well it ran with so many miles on the same plugs.

With firing order 13726548 I pulled the plug from cylinder 1. It looked clean burning "Normal" light brown in color on the insulator and had a gap of over .104+. I expected this because of the high mileage on the plugs.
Cylinder 2 (same condition). Cylinder 3 and 4 slight (Ash Fouled) with .104+ gap.
Cylinders 5-6-7-8 same normal condition as cylinders 1 and 2.
All plugs had a huge gap, all equal at .104-.118. All Motorcraft Platinum Plugs (AWSF32EG in cylinders 1-2-3-4 ) (AWSF32E CYLINDERS 5-6-7-8)

With all the spark plugs in and properly gaped (In Neutral) I noticed a slight delay in throttle response and a little sputtering. Under load in drive I could hear a small back firing from the exhaust..It ran terrible, it strained for power on the highway I was better off with the old worn out plugs installed. I understand that exhaust back firing is an indicator of bad exhaust valve/valves. It never back fired through the exhaust before the spark plug change and had power to spare with the old worn plugs.
The only thing I noticed was cylinders 1-2-3-4 used Motorcraft AWSF32EG and cylinders 5-6-7-8 used Motorcraft AWSF32E
Any information will be very much appreciated.
Thank you,
Rick

 

[sean99]

Did you replace or check your plug wires?

 

[sean99]

http://www.explorerforum.com/forums/showthread.php?t=267532&highlight=plug+resistance

 

[X6StringerX]

If you decide to replace your plug wires, shoot me a PM. I have a brand new set of Motorcraft wires still in the box for 5.0 Explorers/Mountaineers. After examining my wires, I think they were replaced not too long before I bought the Explorer back in October, but I ordered the plug wires before checking everything thoroughly. These things aren't cheap, but I'm willing to take a loss just to unload them and get a few bucks back.

 

[firepop5]

It might be silly to ask, but are you positive you put the wires back correctly? You can't put just one back incorrectly, so if one is wrong, at least two are wrong. If your wires are original, I would definitely replace them.

 

[celly]

Best reference ever (I keep a printed copy in my glove box)

 

[bobflood]

Celly - Great pic - that ought to be a sticky.

 

[celly]

Celly - Great pic - that ought to be a sticky.

Thanks, but it's not mine. I just keep it around as reference, but I did find it on EF originally. I think Section525 (mod extraordinaire) did it originally.

 

[RickMar]

Thank you everyone for all the help, I appreciate it.
CELLY - Thank you for the diagram,
I am going to keep one in my glove box too (Excellent)

 

[Buckeem]

The only thing I noticed was cylinders 1-2-3-4 used Motorcraft AWSF32EG and cylinders 5-6-7-8 used Motorcraft AWSF32E

I am still curious for any thoughts on this issue. Is there a difference concerning the “EG” and the “E” model, or is this a production code?:exp:

 

[RickMar]

Hi Buckeem;
I did some asking around and Internet searches for information.
When the plugs are installed at the factory the plugs go in as "Banks"
AWSF32E cylinders 5-6-7-8 and AWSF32EG cylinders 1-2-3-4. I read somewhere it was something to do with the firing of the engine every other revolution and grounding of the electrodes "Kinda Deep Stuff" Ford engineers dreamed it up for some strange reason.
I have found out the plugs have been superseded by Motorcraft AGSF32FM and is a suppressor spark plug. I picked them up at PepBoys for $5.00 each. No more back firing or running rough, A whole bunch of power now with 220,000+ miles on the clock.
Thank you everyone for all your help I appreciate it very much.
Rick

 

[greaseballpaul]

Thank you!!!

I found another diagram and believed for almost a year now I had my firing order correct. It ran like shi+. I had just done a v8 swap from a rust bucket 97 into my wife's 98 4.0. I let the truck sit for nearly a year after because I was so pi$$ed off after having done all that work (not to mention all the new parts I sunk into it making it perfect) just to have it run bad. Today I realized the whole right bank was not firing. At first 3and4 were not firing with spark all the way to the plug and raw gas on them so I figured head gasket blown between cylinders. When I checked 1and2 and came up with the same thing I knew there was no way and it had to be electrical.

Once I got it together and realized it was not going to run right I got so mad I was to the point of burning it to the ground. This thread was a life saver and I wanted to say thanks. Thank you to the OP of the diagram and to the poster in this thread! THANK YOU THANK YOU THANK YOU!!