Just bought a Taco, has issues

I recently bought my first Tacoma, a '99 2wd 2.4 with a 5 speed manual and it's having issues. On the drive home it would sputter and lose power when you gave it throttle. The issue has gotten progressively worse over the last couple days, with the check engine light coming on yesterday. I ran the code today and all I got was Bank 1 was too lean. I'm gonna replace the fuel filter and the plugs tomorrow to see if it'll help. Any ideas what it could be?

 

I'd be suspicious of the mass airflow sensor.

 

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Give the throttle body a good cleaning to. If it's never been cleaned it'll be coated with black sticky residue. My 2004 was throwing bank 1 lean codes till I cleaned it up. Make sure the idle bypass port is cleaned as well.

 

P0171 System Too Lean Bank 1 is a code that almost always points to a vacuum leak somewhere in the engine bay. I would go over all the hoses and check for cracks or leaks...a big enough one can definitely cause the symptoms you're describing.

Like mentioned it could also be a dirty or failing Mass Airflow Sensor, you can buy some MAF cleaner at the auto parts store and clean it (carefully) yourself...it's easy to do.

Less common culprits are fuel filter, O2 or air/fuel sensor, spark plug wires maybe...but my money is on a vacuum leak.

 

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The previous owner recently replaced the mass airflow sensor so unless he did it wrong I doubt it's the culprit

 

Did he replace it with an OEM one (Denso I think)? Aftermarket sensors are a sure way to get codes on these trucks. A lot of people go aftermarket to save money but should always go OEM when it comes to sensors on Tacomas.

 

Pretty sure it's aftermarket, I'll have to look at it later tonight, I let a family member drive it to work

 

That is probably the issue then I would bet. A lot of threads on this site about people experiencing issues with aftermarket sensors

 

Thanks for the help

 

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Regular cabs rule

 

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