I recently changed my ignition switch from the dealer because sometimes my car would turn off on me while i was driving. Now I am experiencing another problem, which is starting the car. Sometimes, the car starts, but other times it makes a thumping noise and my cars begins to shake. The engine is running but it sounds like it's going to turn off and what do you know, it does. Im not good with cars, so if anyone knows the problem please let me know. Thanks

 

Did it do it at all before the switch problem or now just started after wards?
Do you have the old switch yet? maybe put it back in and see if if it does it or not to help eliminate or point to the new switch.

 

Is the car really cold?

 

You didn't say if its a Type S or not..... but non S had a problem with fuel pressure regulators which would cause a problem with hot soak starts. Updated regulator has a black dot on the top of it, when I was busting out transes on these cars 6 years ago each 00-01 got a new regulator along with a PCM.

There is a TSB for that....

Not sure if thats your problem or not.