A friend of mine has a 2001 Taco with a 3.4, she said it runs like crap and the check engine light is on. I checked the codes and it had a lean bank 1 code, the engine will idle nice and smooth, but bogs once the throttle is open. I test drove it and if I ease into the throttle, it does not bog as bad, but if I floor it, it just falls on it's face.
I'm kind leaning towards it being the fuel pump, she said she replaced the filter and it had a bunch of crud in it. What say you guys? I cleared the code before the test drive and it has not come back on, but the drive was only about a mile.

What filter are you talking about that she replaced? The gas filter? Air filter? I'm betting she has one of those POS K&N oiled air filters and the oil and dirt got mixed together and has fouled the MAF sensor up. Check the maintenance section on this site for the DIY and clean that MAF and I bet she'll run like new again! <img src="/forums/images/graemlins/kewl.gif" alt="" />

Even without an oiled air filter it's worth a try since the cost is only 3-4 dollars.

http://www.4x4wire.com/toyota/maintenance/tacoma_4runner_30k/maintenancep5.html

It was the fuel filter that she had replaced. I pass the tips along to her, thanks.

Yes she does have a POS K&N filter, and yes the MAF was fouled with K&N filter oil. Thanks for the heads up! <img src="/forums/images/graemlins/kewl.gif" alt="" />