Chevrolet: 2002 blazer extreme, blazer extreme, obd11

Question
ok i have a 02 blazer extreme, 4.3 v6. the service engine soon light came on, i know more then likely its nothing but its an annoyance and ive had it for a week now and the first time i took it back to the dealer and they put it on there machine and he said the senser was pickin up somthin that had to do with the gas. the put a new sending unit into it before i bought it for the gas gage. anyway they said it was nothin and reset it, well a few days later it came on again! what do u think could be the cause of this? how can i get it to go off myself or how long will it take for it to go away on its own? also its got 80,000 miles on it and says to use 5w30 oil but ive been told to use 10w30 because of the miles and wear on the motor and would be better on it and help it runn better and give me better oil pressure? which is best and why? thanks!!!!!!

Answer

Marty Hea- Well  first off I would use some good 10/40 oil  and a can of STP- with a good oil filter - that will be more than enough for the motor. you should get better oil pressure also.
  As far as the light , it could be a lot of things ,but if thay got it off and it came back than there is something wrong someplace.  if the gas cap is not on right it can even cause the light to come on. but you have 80,000 miles so it could be a sensor or a part. You can buy a cheep meter OBD11 from (jc Whitney . com ) for under 99.00 tell them I sent you. that will allow you to do your own checking of codes and it will also let you turn the light out if it is a simple thing that is causing it to come on. you can even check your friends codes with it , as it  will fit most all cars. it is a good thing to have.  ok >>