1999 Exp EB miss/hesitation at 40-50mph

[strap21061]

My expedition misses only when driving around 40 or 50 mph. The vehicle vibrates or shakes then if I stomp the gas it goes away. I replaced the spark plugs before this happened. I used Autolite Platinum plugs. Anyone have this same problem? Do you think it can be the plugs are bad and I should replace them with Motorcraft plugs?
Thanks

[way2old]

Does the "miss" occur right at shift point into high gear? If so, it is more than likely torque converter shudder. Let us know.

[strap21061]

When I take off you feel a slight miss from take off, real light. As I go faster it the miss is there. Only when going around 40 - 50 mph is when the truck hesitates hard or shakes. I hope this describes it a little better. Thanks for the response.

[khadma]

Have you checked for any DTCs - Diagnostic Trouble Codes?

Even if your Check Engine Light is not on, you may have a code in the computer.

BTW, what size is your engine?

Autozone will provide a check on your OBDII system for you. If you do not have a code scanner.

Autolite plugs are the same as Motorcraft. Just make sure they are double platinums.

I could also be tranny related too, but check for codes in the mean time.

[carlos80]

I d put some motorcraft plugs in it. Ford engines are sensitive in relation to ignition parts. Make sure they re gapped within specs.

[strap21061]

I got a engine code to come on tonight. I will have it checked tomorrow. I'll also update tomorrow. Thanks for the replies.

[strap21061]

The code was a 301. I checked the coil and it was bad. Replaced it and now the truck runs smooth. Thanks for all the help and replies.