shuddering

I'm having a problem with my 1998 aurora. I just had it into the shop not even two weeks ago for a new radiator and a steering problem. Now my check engine light is on and the car is shuddering when I accelerate and when I'm at stoplights. The engine light starts out as steady then goes back and forth between blinking and steady depending on my speed. I thought it could be water in my fuel line so I put dry gas in and waiting a day or two to see if it helps. Any input would be appreciated.

Get it scanned. If you life in the US, Autozone will scann it for free. If you live elsewhere then you have to do it yourself or take it to a mechanic or dealer. Either way you need to get it scanned.

Sound like it might be the plugs and wires, but get it scanned and we can go from there.