Highway speed car shutters when I accellerate

I have a 1994 Grand Am with the 3.1 engine. When I am on the highway in 4th gear between 55 and 60 if I step on the gas the car starts shuttering and the steering wheel vibrates. Harder I step the worse it gets. Also the check engine light comes on about the first time the locking torque converter engages and stay on till I shut the car off. If I let up on the gas it stops.Could this be slipping in the locking torque converter because of the TCC or converter clutch or am I looking in the wrong place? Any help would be appreciated. Replaced Plugs and fuel filter. Car runs fine at all other times and shifts perfect. Doesn't miss going up steep hills.

Had the same problem with our 3.1 Lumina,it turned out too be the plug wires!! I couldnt believe it either....Worth a try!

I have a 1994 Grand Am with the 3.1 engine. When I am on the highway in 4th gear between 55 and 60 if I step on the gas the car starts shuttering and the steering wheel vibrates. Harder I step the worse it gets. Also the check engine light comes on about the first time the locking torque converter engages and stay on till I shut the car off. If I let up on the gas it stops.Could this be slipping in the locking torque converter because of the TCC or converter clutch or am I looking in the wrong place? Any help would be appreciated. Replaced Plugs and fuel filter. Car runs fine at all other times and shifts perfect. Doesn't miss going up steep hills.
So what was the code?

Don't know the code. I have an OBD1 code scanner but when I put it on I get no flash of Check Engine light. Just stays on. I'm thinking maybe code 39 Torque Converter clutch(TCC) circuit? I've read these cars can have wierd diagnostic plugs. It seems to come on when I'm getting on the highway and about when the converter would normally lock up. Car only has 40,000 miles and the wires look OK but I will try checking them with an ohm meter. I'm hoping for something that simple but it runs fine all other times. Never misses or breaks up and I live up a steep hill. Light goes out when I shut it off then doesn't come back on unless I get on a highway or am coasting at a decent speed downhill. Car shakes pretty good and if I floor it it really shakes. My first impression was wires or coil pack or ignition module but for the check engine light and when it comes on. I don't know much about trannys and am not sure if a TCC solenoid would not allow enough pressure through to fully engage the Torque converter clutch. Thanks for the advice though. I appreciate the help.

Update of problem. Took car to Cottman Transmission. He did a code scan and it showed EGR Solenoid 1, 2, and 3. Now the trouble is the EGR for this car must be bought from the dealer and it is $422 without the gasket and he doesn't have it in stock. Wow what a shock to the system but if I need it and it solves my problem I have to get it. Better than needing Transmission work though, which he says if this doesn't solve my problem I will need a new torque converter plus maybe valve body and other items. Estimate for that is $1200 and up. Thanks again to all who offered advice.

Hello, this is my first Post!! Hey I was reading through here and came across this post, I have a 95 grand am with the 3.1, and I also have the same exact problem, the shutters when from 50-65. I have an automatic transmission, and it seems as if the car shifts into "high" gear and lugs the motor. But if the car does do this, I just simply, "boot it" abit, to get it to down shift, the problem is that you don't want to drive around town, kickin your car down every 5 seconds. :shakehead The car has 140 thousand on it, and I just use it for a daily driver, but it would be nice to figure this out, I am very mechanical, and do all my own work on my cars, so I would be fixing this on my own. My friend who has a 97 grand am, same engine, had the same problem, and he said that it is the Lock up function on the tourqe converter, and the "disconected the wires for it" Well, I have been looking in my manuals, and under the hood, and found some wires, but am a bit leary to just disconect them. Also, last spring I did plugs on the car, and found that the number 1 and 3 plugs had tons of white chalky deposits on them.. the number 1 was almost solid. lol. Last week I thought maybe I will look at the plugs quick, and sure enough, same thing, just on those two, although not as bad, but well on there way.. So the reason I am posting is that I think we may have the same problem, and I am very intrested in finding out what you did, and if it has worked.

Thank you for your help.