99 300M ignition problem

My 99 300M has run great. a couple of weeks ago it sort of hesitated then shut off. It started back up immediately. I put some fuel injector/dry gas in it. Hasn't done it again. Today I was doing some running car was running great. Stopped got back in it cranked started to start then wouldn't. Cranked great. It normally starts on first crank. Tried for about 3 minutes nothing. Was ready to give up and it started and has started everytime. There was no ck eng. light nothing. I took it to my mechanic and it had no computer readings and the fuel pump pressure was 50. Any ideas. I just don't want to be left sitting.

Nothing from the computer is odd, if it has happened since then have you gotten any codes from the key check? Turn key to 'on', but do not go to crank it, bring key back to 'off', do that three times on the third time hold it at the 'on' position. It should show any codes, if there are any, in odometer display follwed by 'done'.

My first though is a battery connection issue, loose or corroded cables/posts, but no codes makes me think it might be something else.

It just happened the once today, I have been driving it and it hasn't happened again. It was almost like it was getting gas or park. The fuel pump is showing it is putting out. The fuel filter is part of the pump so I hate to change that if it isn't necessary. It took about 3 minutes of cranking then all of a sudden it started like nothing happened. The mechanic couldn't find anything

Do what windowpane suggested to see if any codes are thrown off. Other than that maybe it is a cam sensor, but it, too, would throw off a code.

Hi I had the same problem with my 300M. It didn't show any codes either. My mechanic fortunately deals alot with 300M cars. He suggested a crank sensor going bad. We changed it and so far so good. That was about 7 months ago.

thanks

Possibly a leaky fuel rail, too.