Hi there everyone... new to the forums here, been lurking a while, and did some searching but couldn't find what I'm looking for, so decided to make a username and join the forums, everyone seems very helpful afterall.

1999 Ford Ranger 4.0. 160k+ miles on it, just got it a few months ago.

Yesterday it threw a CEL at me, and read the code, it said P1151 HO2S21 lean

My first thought was the MAF, and I could blow it out or soak it in paint thinner for a while to clean it up... but what about the H02s21 lean... that makes me think it's something other than the MAF? Anyone have experience with this, can you point me to best first steps to fixing this...?

EDIT: Yesterday it ran fine all day with the CEL, no shaking or anything other than the CEL. Today's cold start it stalled and took a long time to start, then ran fine.

FYI I've been driving on a military base for the past 3-4 days in a SUPREMELY dusty enviornment... all the roads are covered with something like moon-dust and you can only go about 15mph before you lose sight of the person in front of you due to dust cloud...

I pulled my airbox and it's pretty bad but not awful... blew it out and cleaned it, been wanting to swap for a K&N anyway so this may not be a bad time.... what about getting a replacement MAF from a junkyard truck? will that work or is it frowned upon?

Thanks in advance

 

I have fog/driving lights on my truck had a similar situation as in my fog lights (both) stopped working....for no apparent reason. Short time later they came back on. Long story short, (I know...TOO late!) it turns out ford has a CANCELATION SWITCH that kills the "low beams" when you hit the "high beams"! After I did a lil checking, that was it. Just a thought. You might have that cancelation switch on your truck which be cool. BTW- THIS IS MY FIRST ATTEMPT TO POST. FELT GOOOD My apologies for posting here. It was meant in the thread before. THANKS, Boxmacker