I have a 99 4Runner with 200k on it. It keeps kicking the lean fuel code. I've ckeaned the MAF,that helped some still kicked the code. I changed both oxygen sensors and installed a complete exhaust from manifold back. That also helped it run a lot better. Still kicking the code. Every time I reset the ecu it runs horribly for the first couple minutes then steadily gets better. It idles good and runs good now but still kicks the same trouble code. Any advice would greatly be appreciated thanks!!

 

Just what code are you getting??

 

clean the throttle body. you might even have a vacuum leak you could check this by looking at your idle air bypass data on a scan tool. maybe its time to test the 02 sensor since its probably stock.

 

I'm getting trouble code p0171,which has quite a page of possible causes. The mass air was filth so I cleaned it with alcohol and a q tip gently. I also changed the fuel filter. Thanks old blue for the tip. I'll check and clean the throttle body. Both O2 sensors have been replaced.

 

Maybe time for a New MAF I had to replace a few before 200 ,000 miles.

With that code a live scanner is your best bet Like you said a whole bunch of things

I would be looking at the coolant temp sensor next if you have not all ready

Remember these engines like Toyota Sensors.

 

Thanks wyoming9. Any suggestions on a live scanner? I've been debating on getting some kind of scan tool.