Engine running lean

[Warduke]

I keep getting 172 and 136 engine codes when I reset the computer. What causes the engine to run lean? Does this mean im wasting fuel thats not burning? Or burning too much? Car is a 94 3.0 with 152k

 

[1993MTXSHO]

look here youll get most of the answers you need. Iv been chasing my ass on this for about a month now and I think I finally figured it out, but well see ina week.

http://www.shoforum.com/showthread.php?t=84670

 

[shovermont]

could be bunk 02 sensors

 

[ultimatesho]

replace ur O2 sensors

136 (R) Oxygen sensor not switching/system lean Left or Front HO2S - Fuel control

172 (R,M) Oxygen sensor not switching - system is or was lean - Single, Right orr Rear HO2S - Fuel control

means both O2's are probably bad, same codes my 92 gave me when its O2's went out

 

[Warduke]

Thanks, Is there any real reason why I should not buy the bosch $40 oxygen sensors? I see they sell ones all the way up to $90 for standard oe replacements. Whats the difference besides price?

 

[shovermont]

nothing, OE is just more expansive and lame. i would buy your local auto parts store ones. online they are probably cheap too. your car will run a lot better. i wouldnt run them without it. you dont wanna be leaning your motor out, could mean real bad news. its an easy simple 10 minute fix too so get it done.

 

[Lightning]

What causes the engine to run lean? Does this mean im wasting fuel thats not burning? Or burning too much? Car is a 94 3.0 with 152k

Generally speaking, a 'lean' mixture is a case of less fuel than the perfect ratio of 14.7:1 - not enough fuel...

Sorry, I am quite under the weather right now or I would get into a detailed discourse on the subject, but a few minutes searching here and on the web should yield much information on the subject.

This should get you started if you are interested:
http://en.wikipedia.org/wiki/Air-fuel_ratio

 

[blue thunder]

Ya boss anytime your car is running like shit to the point that it is staulling or your getting about 10 miles to a gallon its the O2 sensors. Mines been running like that for about 2 wks now. I'm finally going to change them on friday when I get my check. there easy to change and theres two, one has a longer wire thats it. There about 40 to 50 bucks a piece. Good luck.

 

[SHOtime2511]

wouldent hurt to give your MAF a good cleaning too.

 

[1993MTXSHO]

read my thread I posted, my o2's are reading lean, my emissions test indicated pig rich, id hate to see you replace the o2's and have the same problem.

 

[ultimatesho]

read my thread I posted, my o2's are reading lean, my emissions test indicated pig rich, id hate to see you replace the o2's and have the same problem.

o **** boy u dont count!!!!!!!!.......we all no u have the weirdest luck of anyone on here

 

[Storm-Chaser]

. . . or worse yet, waste a $100 on sensors and not correct the problem. Btw, you can get OEM sensors for much less than $90 each.

Do a search using the OBD codes and read a few of the longer ones to you get an understanding of what can cause those codes to set.