Igniton Troubles

Here's the problem:

I just got my car back from the mechanic. He change a water pump inlet pipe becouse it was corrodide,rusted and was leaking. He said that he needed to take the whole engine out to get to the pipe.

When I'm driving home from picking up my car it sputters when you get to higher speeds and RPM's and the check engine light turns on. This has never happened before.

Now it turns on when the engine is cold and still sputters sometimes. But if you try to turn the engine on right after turning it off it turns on but quickly shutsdown and won't turn on.

What could be the problem? Did the mechanic do something wrong?
Any help will be greatly appreciated.

take it back to the mechanic. if you get it back broken then its his fault and he should fix it. demand that he fix it cause it worked before you brought it in there

the mechanic can and will always say its not my fault that just happened coincadently lol. sounds like a sensor problem easy fix if the check engine light is on. only problem is he took ur engine out to get to it? everything is pretty much replaceable with the engine in there so that sounds shady. check ur engine code from the ecu... sounds like a sensor is bad just cause of the sputtering n shit.