cel p1153 p1171 HELP!!!!!!

[9passport7]

just recently bought a 97 passport, like it very much.
but....shortly after i bought the check engine light came on. checked the codes and it said...
p1171 fuel system lean during acceleration
p0143 h02s circuit voltage low back 1 sensor 3
p0137 ho2s circuit voltage low bank 1 sensor 2
i talked to a mechanic and he said it could be fuel filter, pressure regulator, or fuel pump. so i replaced the fuel filter, didn't do it.
checked the fuel pressure and tested the pressure and the regulator wasn't quite up to snuff so i replaced that, didn't do it either. no it spit another code at me....
p1153 ho2s insufficient switching bank 2 sensor 1
now i'm really confused!!
my guesses would be maf, intake gasket leak.....
oh yeah the first thing i did is put new plugs in, but they were bosch plat. is it really that important to have nippondenso??

thanks for any help

[Canucklehead]

How many miles on you Passport?

Did your mechanic suggest you maybe try replacing your O2 sensors (seeing as you had codes that indicated that three of the four sensors aren't operating properly)? You can get replacement Bosch O2 sensors from AutoZone for about $50 apiece. If I'm not mistaken, Bank1 Sensor1 and Bank2 Sensor1 are used to control fuel mix based on )2 content of the exhaust.

[9passport7]

120,000 miles
no he didn't, visually they look brand new comparing the o2 connector to the harness connector. may not be worth much though. what is the best way to test them?

[rodeo02]

Check/ listen for vacuum leaks & check your mass air flow sensor.
G/luck
Joel

[9passport7]

how do you check your maf sensor

[rodeo02]

Originally Posted by 9passport7

how do you check your maf sensor

About the only thing you can do is see if the probe is coated in oil/dirt/gunk (common if you use a reusable/oiled air filter), or try to clean it with spray electrical cleaner & a cotton swab. I dunno of a way to bench test it.
G/luck
Joel

[2eyefishclaw]

was the problem there before you installed the new plugs
if not replace the plugs with NGK plugs because these BOSH plugs can be causing your problem and can eventually cause damage to your catalytic convertor

[9passport7]

no i put those on right after the cel came on