Trouble codes HELP

[dragonboi]

I have a 1997 ranger with a 4.0L

it has the codes saying lean fuel bank left and lean fuel bank right

jumps at idle between 500 and 800 very rapidly and dies some times

have replaced air filter, fuel filter IAc and cleaned MAF sensor still codes

help me out please

 

[timstone]

check for vacuum leaks...if none are found check o2 sensors

 

[dragonboi]

check for vacuum leaks...if none are found check o2 sensors

has two new o2 sensors but does have 128k

 

[timstone]

ok...well maybe check to make sure you are actually getting spark to each plug

 

[Earl43P]

There is a wealth of info on those codes, if you used the Search. "P0171 P0174"

Might have a vacuum leak, might have bad upper and lower intake gaskets (likely since it's both banks). Pretty common problem. I'd inspect all the PCV tubing and elbows and replace the intake gaskets if you don't find anything else, like a loose intake tube.

I'd believe the O2 sensors are telling the truth.

 

[modelageek]

IT IS NOT YOUR O2 SENSORS!! I agree with Earl. I have seen a lot of posts about the intake gaskets causing the lean codes and also there is a hose with a 90% elbow on it that i have seen cause an issue. I cant remember what year 4.0 it was/is. you also might want to do a fuel pressure test if you have the means.

 

[dragonboi]

ok thanks for posting everyone i really dont want to delve into gasket replacement but it looks like i might have too

oh well i need it to run right, its my only means of transportation