stalling????

i have a 97 blazer that i baught in july this year. it only has 69,000 on it. when i baught it i figured i would do a tune up like usual- i replaced the oil and fuel filters pcv valve and i cleaned the throttle body. since then, it stalls without warning. it always starts and never kicks on the check engine light..
could the fact that when i changed the oil and i put lucas oil in it, cause this problem. i dont know much about this year blazer so i was wondering if maybe the oil is to thick now and is tripping a sensor? also i have a srange clicking under the passenger side floor when i turn, everything on the passenger side of this thing was replaced (at no cost) and it still makes the noise. anyone have an idea?

You need to check the ignition switch. Your year is known for defective switches.

thanks for you advice. i checked things out and it turns out that my fuel pressure regulator went to sh!t on me. i took today and replaced it. you would be amazed at the difference.... thanks again!!