I've read several posts on this site, and I'm still not sure whether the shudder at 1700 RPM (feels like a mis-fire under load) is related to weak coils or a tranny shifting problem. It only happens as the transmission is up-shifting or into OD at this RPM. Last fall, I got a P0301 misfire while towing the horse trailer and it ran terribly for 2 days. With no intervention, it started running better, I cleared the code and since then I have noticed this problem which could also be described like a transmission shudder during the shifting.

98 SuperCab 4.6l
New Fuel & air Filter
New plugs (Motorcraft) & wires <20k ago
New EGR valve recently

 

I would replace the coil packs - after 10 years - it's due and there not expensive if you order on line.

 

I had the same problem around 35-40 MPH during shift

problem went away after trany power flush, and yes- change coil packs my milage improved when i did.

 

Before replacing the coil packs, try putting some dielectric grease in the wire boots.

 

I had the same problem it was the ground wire on one of the coil packs.

 

however if you do decide to replace a coil pack, go with OEM. i just bought some new MSD packs and im not impressed with a fresh coil pack giving me misfires when a OEM coil pack that has 194k and is at least 11 years old delivers a smoother idle on my motor swap