Not sure if this is entirely the right place to post this, so I apologize beforehand.

A little after I start the car (around thirty seconds or so), the "service engine soon" light blinks a few times and the car starts shuddering. If I keep tapping the gas or hold it down a bit, it won't do it until I let up. I've changed the spark plugs, spark plug wires and the ignition coil. I even changed the valve cover gaskets and spark plug tube grommets, but I can't seem to figure out what the problem is. Has anyone had this problem? I'd really appreciate any advice.

 

If more details are needed, I can provide them. I've gotten really frustrated with this. I can't seem to figure out was it is.

Also, I forgot to mention that it's a 2004 base model.

 

Pull a code...
Sounds like a misfire....
On a "cooper" it often means a valve issue from not using midgrade 90 octane as required.....
If the wires, plugs and coil are OK...
Time for a compresdion check then a leakdown to narrow it down...
But pull a code....maybe you will get lucky and it is a sensor causing it....
If it is a misfire....a mechanical fix (new valve) is thevlikly fix....