Here is the deal ... my truck is throwing the p0171 and the p0174 code... it is coming out as a left bank lean and right bank lean codes... i was wondering if neone could tell me if it is the front or rear o2 that have went bad... my truck has 57000 miles and no cat mods and it isnt idiling weird but it has slown down some in the past week as far as my little "1/4 mile strip" somewhere near 5-6 mph (but i have also installed a snugtop bed cover and a bed rug)...first it threw the p0171 and then i went back bout 3 days ltr to make sure that was the right code and the other one was thrown too and well now i need to know which ones i need... so i hope the info i gave would help where i can get this prob worked out... thanks a lot...

 

Have you done ANYTHING recently to the truck? Usually those codes don't show up unless there is a vacuum leak around the intake manifold or an exhaust leak around the O2 sensors.

It only takes a small vacuum leak to cause those codes to come up.

 

well a while back i did an egr block off and well i took it off when it threw a code and well it is still throwing them ... i did install two rear ones today and it threw a code again and well i am goin monday to get the front one in exchange for the rear ones... i think that might be the problem.... what u think??? oh and a while back i did the other egr mod and cut the pipe in half and epoxied it back and well the code was thrown like a week 2 weeks after that and i dont think that caused it... i just think it was time... b/c one was thrown and like 4 days ltr both were thrown...thanks

 

If there is a leak around your EGR it will throw those codes. I would check that before replacing all the O2's. All I've ever heard about the EGR mod was how many problems people had getting the gasket to seat properly and seal up.

Check it out and reseal it. Are you reseting the computer after each attempt at getting rid of the code?

Let us know what you find out.