I just bought this 93 pontiac. It has 224,000 miles on it. Its my first pontiac so I am trying to figure out some problems it is having. The car is in great condition as far as paint, body, interior, wheels, and the price was right. I figured I would have to do something major to it. Just trying to figure out which or what is wrong.
First, the engine is just dogging right now, it purrs on the highway, but idles rough. I put new plugs and wires in it. It didnt make a real difference. I didnt see any visible oil leaks, it doesnt smoke, no water in oil.
Second, it has a bad shake while driving, when let off the throttle it will stop. This happens at 70mph or 30mph. So far from what i have read thats from the transmission. I took it to the transmission guy and before he even drove it he said it needed tuned up first. So as you can see i am not sure what to try next.
Ignition coils?
Thanks for any info

If you read through the forum, you will find that rough idle is common and the FIRST item to check is the EGR valve. THis part failure is "NORMAL" at this age and the symptoms you describe are part of it. Looking for anything else is useless unless the EGR issue is cleared first. Price is 75 to 250$, depending where you take it.
www.avigex.ca/xport/egrvalve.jpg
www.avigex.ca/xport/egr3.jpg
YOu also ought to pull the codes to have a glance at possible troubles.
www.avigex.ca/xport/readingdiagnostics.jpg
www.avigex.ca/xport/3800codes.jpg
www.avigex.ca/xport/plug.jpg