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Discussion Starter #1
Good Day Lexus community,
i have a 2002 is300 sportcross with 223k miles. Over the past 3 years i have been fighting with a number of codes and working my way down and now i have been completely stumped. i bought a new car so i dont have to deal with the issues anymore but i still want to get her fixed up. I've had the car for 8 years and aside from the CEL i still love the car.

The first few issues i had were evap and catalyst efficiency below threshold so i changed the cats and the fuel tank check valve and cleared those codes.

P0156 showing b2s2 heated sensor malfunction has been pending and i changed both bank 2 o2 sensors with the same code pending
I got it down to 2 codes the p0156 pending and P0174 so i smoked the car and found that the o-ring for the elbow on the manifold that goes to the PCV was leaking so i changed the o-ring and its not leaking
Somehow that caused the P0171 to come on along with the P0174
The P0171 and P0174 codes i have tried going through the forms for months on it and most people fixed their codes with a MAF or changing vacuum hoses.
ive cleaned my MAF to no avail and then replaced it to no difference
Ive changed every hose that i can find with the throttle body off so i can see underneath. the only hoses i didnt change was the small ones going to the actuator for the intake baffle
ive cleaned the throttle body and air intake along with putting seafoam through the tank every month to try to clean the fuel system
I also changed my valve cover gaskets and cleaned my plugs because they were drowning in oil thinking that was causing less spark and i changed the fuel filter and strainer thinking it just wasnt getting proper fuel. i also changed the throttle body and upper intakemanifold gaskets
i get a loss of power between 2-4k only on highways though
im at a loss here. HELPP

for anyone that doesnt want to read all of that ill just list the parts that i have changed:
plugs about 8k miles ago
both bank 2 o2 sensors
valve cover gasket
fuel filter and strainer
air filter
most vacuum hoses
throttle body gasket
upper intake manifold gasket
pcv valve
might be forgetting a few small things
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