I have a 1995 Chevy 4x4 1500 with a 350 engine. I am getting horrible gas milage although the engine runs extremely well. The engine light will come on from time to time and when I had it checked it said it was the "Mass Airflow Indicator". We have looked everywhere for this sensor. It is not on the airhose to the carb. like I have seen in just about all the pictures. I need to get this fixed before the cost of gas breaks me.

I am sorry...I should have started my reply with a THANK YOU FOR YOUR HELP WITH THIS. I really do appreciate the help and do believe your are correct about the PVC valve.....Mark I am sorry...I should have started my reply with a THANK YOU FOR YOUR HELP WITH THIS. I really do appreciate the help and do believe your are correct about the PVC valve.....Mark

I replaced the PVC valve and disconnected the battery for about 10 minutes to reset the system...the "Service Engine Soon" light came back on within 3 miles. I replaced the PVC valve and disconnected the battery for about 10 minutes to reset the system...the "Service Engine Soon" light came back on within 3 miles.

Check your O2 sensors if they are clogged, reset and pull your active coes again Check your O2 sensors if they are clogged, reset and pull your active coes again

The problem is no one can find the O2 sensor on this truck. The problem is no one can find the O2 sensor on this truck.

http://www.truckforum.org/forums/attachm... http://www.truckforum.org/forums/attachments/chevy-truck-forum/1105d1216411861-oxygen-sensor-replacement-help-41927858.gif

Add Its on the exhaust in front of the catalytic converters, it may have more than one. Looks like s spark plug with a wire coming out of it. You know it could be someone has tried to remove the emissions off your truck Add Its on the exhaust in front of the catalytic converters, it may have more than one. Looks like s spark plug with a wire coming out of it. You know it could be someone has tried to remove the emissions off your truck

Thank You Very Much ATP1962..I blew up your diagram to plus 400 so I had a very good look. The man at NAPA looked there as well and there is not one nor can I find anywhere where one could be screwed into at. I have a not-so-smart question and I am sure I aldready know the answer but just to be sure, I am fairly certain the instument that looks like a spark plug that is inbetween the first two actual sparkplugs in front on the driver's side is a temp gauge and NOT the o2 sensor. It has a single blue wire coming from it. Thank You Very Much ATP1962..I blew up your diagram to plus 400 so I had a very good look. The man at NAPA looked there as well and there is not one nor can I find anywhere where one could be screwed into at. I have a not-so-smart question and I am sure I aldready know the answer but just to be sure, I am fairly certain the instument that looks like a spark plug that is inbetween the first two actual sparkplugs in front on the driver's side is a temp gauge and NOT the o2 sensor. It has a single blue wire coming from it.

The oxygen sensor is in the exhaust pipe but can be in the exhaust intake. On newer models they are in the exhaust Y pipe, in front of the catalytic converter, and some have on front and back of converter on newer models. Alot of guys eliminate them when they customize the exhaust which cause problems suck as yours. A bad electric choke can cause issues as well. The oxygen sensor is in the exhaust pipe but can be in the exhaust intake. On newer models they are in the exhaust Y pipe, in front of the catalytic converter, and some have on front and back of converter on newer models. Alot of guys eliminate them when they customize the exhaust which cause problems suck as yours. A bad electric choke can cause issues as well.

Thank you so much again. I have about decided to reside myself that it was removed as you said. I thought I might run it up to the Chevy dealership and see if they would take a look. Except for the low gas milage and that dang S Thank you so much again. I have about decided to reside myself that it was removed as you said. I thought I might run it up to the Chevy dealership and see if they would take a look. Except for the low gas milage and that dang S

"Service Engine Soon" light...it runs like a dream. "Service Engine Soon" light...it runs like a dream.

Could it be your emission stuff was removed from this unit? Or could this be a replacement motor? So many things dont add up. I could check your timing on this unit and your choke setting then Could it be your emission stuff was removed from this unit? Or could this be a replacement motor? So many things dont add up. I could check your timing on this unit and your choke setting then