My car starts fine maybe 2 out of 5 times the other 3 times it has a real long hard and grinding sort of start....I got a feeling its the knock sensor actin up again because if I remember right it did the same thing when it went the last time a couple months ago and then it just stopped starting all together, also I don't think its my starter cause I changed that about a year ago...any advise or ideas would be great....thanks in advance

 

The knock sensor has nothing to do with that. Sounds like starter or flywheel.

 

Check your fuel pressure. Possibly a fuel pump problem.

 

how do I check the fuel pressure?? yeh I think it could be the starter but I don't know I doubt it cuz i got it changed last year....thanks again guys