I need a little help trying to figure out why my truck is having trouble starting up. I recently had the following work done...
-tune up... ie. new wires, plugs, fuel filter, cap, pcv valve.

I figured the truck would start up better after the tune up but it did not. So i hooked up my obd2 scanner and found that the throttle position sensor was not working correctly. I replaced it and it still starts up rough. By rough i mean i have to crank it once, stop, then on the second crank it usually turns over. If the truck is cold it is worse. If it is after a warm start it usually fires up.

So, taking my mechanics advise which was a bad fuel pump, I dropped the tank and replaced the pump. Still starts up rough. I replaced the fuel pump relay switch. That also did not work.

I am really at a loss as to why it is not starting up correctly. The truck has just under 80k miles. Someone said maybe a bad crankshaft position sensor... I don't know. It has the 4 cylinder 240sx engine in it i believe... the stock one.

Any help would be greatly appreciated.

thanks[:@]