99 4Runner fuel injector problem

[Grantbd]

A few months ago my check engine light came on. I couldn't tell that there was anything apparently wrong with my truck, so I brought it to the shop to get checked. They told me that the engine was running lean, probably because the fuel injectors were getting clogged. They told me that because of the particular injector used on 4Runners, cleaners won't work and the only thing to do is replace them all, totaling around $2,000.

Is this true or are they just trying to sell me parts and labor I don't need? If I was to use a cleaner, which is the best?

Truck is 1999 4Runner with about 110,000 miles, 5VZ-E engine

Thanks for any input!

[Brian R.]

Welcome to the AF!

I don't know of anything special about the injectors on a 5VZ-FE that would prevent being cleaned. Normally, when you have a lean condition from injectors, putting cleaner in the gas is not enough. You have to run cleaner through the injectors directly. You can search the internet for injector cleaning kits.

There are a number of other problems that can cause a P0171 "System too Lean (Bank 1)" DTC. What triggers this code is when the air fuel ratio feedback is stable after engine warming up, and the fuel trim is considerably in error on the LEAN side (2 trip detection logic)

Check your air intake hose and make sure it's not loose.
Check your fuel line pressure and make sure it's not low (may be triggered from running out of gas). If you fuel pressure is low, check the regulator, then the pump. Filter is least likely.
Could be Injector blockage
Could be your HO2 sensor
Could be a MAF meter malfunction
Could be an engine coolant temperature sensor malfunction

Remove and clean MAF meter with electronic circuit cleaner<= most likely
Fix vacuum/intake leak downstream of MAF meter
Inspect fuel lines for cracks, leaks, or pinches
Check fuel pressure at the fuel rail - Check regulator and pump
Replace fuel filter
Check output of HO2 sensor
Check injector performance - clean
Check ECT sensor voltage output

See the 2003 Tacoma service manual in the sticky post at the top of this forum. The engine information is applicable to your vehicle.