ok, so when my car is cold..starts great but when i drive it for little bit, and i turn car off..car slowly cranks n kills battery...any ideass

 

i would suspect that the starter is getting tired. have a starter draw test done when its warmed up.

 

may as well have the battery load tested and check alternator output while youre looking at the starter. Also, check battery cable connections for tightness, corossion etc.

 

well i test drove it today n felt lil sluggish after warmed up then shut off after few minutes then slowly cranked...i was thinking maybe crank sensor as well

 

Cranking slowly and the sluggishness are hopefully unrelated. The only way they could be related would be if the car is overheating. If the car was over heating to the level it was sluggish you are risking major engine damage.

Assuming you are not overheating you most likely have two separate issues that happen to arise about the same time. The crank sensor tell the computer where the crank it. This is for the ignition. If it was failing you would have a random miss and the car would run rough not sluggish. Most of the time when the crank sensor fails it is because of a cracked magnet which causes a no start condition.

 

one may be a low fuel pressure problem. check fuel pressure.

 

Also in many cases when a starter or cables start to go bad heat makes them worse. So if the starter or cables where “almost” bad any condition that raised under hood tempters would cause the slow cranking to show up and anything that cools under the hood could seem to make it go a ways. In the end this would only happen with a started/cables that are close to the end of their life.

Example: car comes in with your exact complaint. I find the Cat is partially plugged. This causes the engine to be sluggish and the motor is getting hotter than normal. I replace the Cat. Starter passes a draw test and the car seems fine. 3 weeks later the car comes back in with a slow cranking starter that fails the same draw test it passed 3 weeks ago. Customer is pissed and thinks we did something to make the starter go bad. Live and learn

Edit: I am not saying I think your cat is plugged, that was just an example. Anything that car increase the underhood or exhaust temp can effect a weak starter. 

 

I checked the fuel pressure n starter..both perfect..so now i believe its the crank cause i looked up the crank sensor failing symptoms...and it matches up. lets hope forthe best