Spark plug question

Some of you might remember my post a few weeks back about a miss in the engine that felt like a secondary ignition problem. I had already changed plugs and wires, and ohmed the coil packs, and later put in a new DIS module. All of these have not cured the miss. The tech at my dealership (who is very knowledgeable and does good work) asked me what brand of plug I put in, I told him Autolite double platinum. He said that he had a lot of troubles with Autolites because they do not have the resistance that the MotorCraft plugs do and that has caused several cars he has worked on to miss similar to the miss I have. So my question is, is he correct? I looked at the old plugs, they were Motorcraft AWSF32PG 's, now nobody seems to stock those, so are the AWSF32PP a suitable replacement. I know that the PP's are double platinum, but are they the superseded plug for the PG.

Thanks
Thumper

Plugs

Looking at my notes the actual replacement plug for the SC engine is the Motorcraft AWSF34PP. They are the long plug that reaches into the combustion chamber a little farther. The AWSF32PP plugs are shorter and run a little cooler since they are not in the chamber as far.
I just installed Autolite APP764 plugs (similar to the shorter Motorcraft AWSF32PP) gapped at .048 with no problems. I have also installed Taylor SpiroPro wires and the engine runs great, Very smooth.
It's difficult to say that the plugs are the cause. Do you get the check engine light? And is you vacuum at idle around 18-20?

blue94sc said:

Do you get the check engine light? And is you vacuum at idle around 18-20?

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No lights and the vaccuum is great. The engine will spin 5500 rpm without the miss if you run it out in a low gear, then second, third, so on, but if you put throttle pressure on a a lower rpm it will start to pull then miss a few times. In other words (I hate that phrase) when the igniton is under it's highest load (demand) the miss occures, but not when it is just make lots of pulses (rpm) it works just fine. Its is also heat related, if the engine is dead cold it pulls just fine, as it warms up it starts to miss a little then when at full temp it will miss regulary.

Thanks
Thumper

Look at your coil pak closely

I had a miss problem in my 94. It got worse over time to the point the car would quit. One day I was going home and I could not accelerate hard but I could drive the car and accelerate easy enough to get it home. When I got it home and I started looking. I had a spare coil for my XR7 that I was going to put on the 94. However, when I removed the coil off the 94, I turned it over. There was a buldge on the bottom and white stuff was leaking out. I replaced the coil and it ran great. Hope this helps!

Ed Springer

90 Black XR7 5-speed: 70mm TB, Fresh Air Intake, '94 Supercharger, 5% SC Pulley, Raised SC Top, I/C Fan, UD Pulleys, 190 l/h Fuel Pump, 36# Injectors, Headers, Magnaflow Muffler (no cats) with stock resonators, 3:27 Gears, Ripper Shifter, 73mm CL MAF (Blue Tube), Magnacore Wires, NGK Iridium Plugs, Royal Purple Lubricants and Rear Spring Air Bags.

94 Red SC Auto: 70mm TB, Fresh Air Intake, Stock 90 SC Pulley, Raised SC Top, I/C Fan, 190 l/h Fuel Pump, 38# Injectors, Headers, Raven Muffler (no cats) with stock resonators, 3:73 Gears, 76mm CL MAF (Gold Tube), Magnacore Wires, NGK Iridium Plugs, Royal Purple Lubricants, TRANSGO Shift Kit, Pro-Torque 2500 Stall TC, Haydon Auxiliary Transmission Cooler, Tokico Struts & Shocks, American Racing 17” Sniper Wheels, Michelin Pilot Sport A/S Tires and 235 RWHP with 315 LB-FT Torque.

edspringer said:

However, when I removed the coil off the 94, I turned it over. There was a buldge on the bottom and white stuff was leaking out. I replaced the coil and it ran great. Hope this helps!

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Pretty sure it is not the coil, both primary and secondary side ohmed out ok, no swelling or leaks and all the terminals are bright and shiny. Still thinking its the plugs, as soon as I can get some ordered I'll slip a new set in.

Thanks
Thumper

I'd say it is definitly the plugs. Autolites were the hot plug for the gusy in my truck club for a while, mainy becasue of the price of them. Recenlty, most people have been switching to different plugs and not recomending the Autolites due to rough idle and misfire codes. You get what you pay for and Autolite isn't the best quality plug. I'm running NGK iridium plugs in my Bird and havn't had a problem with them. Had to order them online, but they arrived quickly.

HSKR said:

Recenlty, most people have been switching to different plugs and not recomending the Autolites due to rough idle and misfire codes.

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Thanks for the input, I did get the Autolites on a "deal", buck a plug rebate, what a deal. I am going for a set of AWSF34PP in a few minutes. I have been noticing a bit of a rough idle so that helps to confirm a plug issue. I'll have to wait til the weekend to put the plugs in because it is the wife's daily driver. It will need to be stone cold before I will pull plugs out of an aluminum head, even with the anti-seize I put on them when I put them in.

Thanks again
Thumper

So I have been on a two day quest for AWSF34PP, and nobody seems to have them. Does anybody have a source for that plug, or what do you supersideways them to. I have been pointed toward a FM suffix but that comes back as a fine wire center electrode. I am not sure that these will hold up, so help me out here a bit.

Thanks
Thumper

I couldn't get any AWSF34PP's either, was redirected to their replacement of AGSF34FM stock number 6104. They have been in for around a couple of thousand miles with no trouble. I hope that helps.

Michael Mattix said:

I couldn't get any AWSF34PP's either, was redirected to their replacement of AGSF34FM stock number 6104.

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Thanks, I guess I'll go for a set of those.

Thumper

Try NAPA?

My local NAPA store just happens to have the AWSF34PP's in stock.
They quoted me around $5 a plug. They stated that they don't stock a whole lot of Motorcraft plugs. Only the real popular ones.

spark plugs

well you guys got me wondering. I just ordered some double platinum autolite's but the number discountauto.com($4.59ea) and autozone.com(2.99ea but temp. out of stock) was APP2544. any idea if I'm getting the correct plugs? I have allways had good luck with autolite's in small block Fords but this blown bird is new to me.

bloodybobber said:

well you guys got me wondering. I just ordered some double platinum autolite's but the number discountauto.com($4.59ea) and autozone.com(2.99ea but temp. out of stock) was APP2544. any idea if I'm getting the correct plugs? I have allways had good luck with autolite's in small block Fords but this blown bird is new to me.

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The APP2544's I believe are the equivelant to the Motorcraft AWSF34PP plugs.
They are the longer (stock) style of plug. The APP764 plugs are shorter and tend to run a little cooler than the APP2544's.
It is the correct replacement plug only manufactured by Autolite instead of Motorcraft.
Just personal preference.

bloodybobber said:

well you guys got me wondering. I just ordered some double platinum autolite's but the number discountauto.com($4.59ea) and autozone.com(2.99ea but temp. out of stock) was APP2544. any idea if I'm getting the correct plugs? I have allways had good luck with autolite's in small block Fords but this blown bird is new to me.

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Don't do it, you'll be sorry. I just put a set of AGSF34FM Motorcraft plugs in the the car runs sweet. My wife drove to work and called me to say thanks for the "new" car, nuff said. I did take the Autolite APP2544 plugs back to the green guys (O'Rielly's) and they did give me a full refund, which was nice of them. However nice that was it still does not make up for the three or four months of chasing and replacing that it took to come to the conclusion that the "almost new" Autolites were junk. To all my advice would be to stick with the Motorcraft AGSF34FM gapped a .054.

Thumper, and more importantly, Thumper's wife (Bambi of course) are living in Pleasantville again.

Thanks to all who offered input

Thumper

It is possible to get one or more crappy plugs in a set. I have run both the Motorcrafts and the Autolites and I haven't noticed a speck of difference in them. Just another data point.

Jon