PO171 issue

A

ABN

New Member
Truck has po171 code no vacuum leak , new pump, filter etc. runs good when cold then stats missing and hard to start. has anyone had this issue? also replaced O2 sensor upstream, coils and wires. filter and mas flow sensor.
 
Just looked up the PO171 code. I'm making some assumptions about your truck. You haven't provided any details as to year or model or engine.
I'm assuming you have a Gen2 V-6 (1GR-FE)

The following is from the "2005 to 2006 Tacoma OEM Repair and Wiring Manuals"

Anyhow, this code flags as a System Too Lean (Bank 1).
1679755944098.png

You probably need to schedule a visit to the dealer. The diagnostics get pretty complex and need specific meters for measurements.

Possible contributing causes......
1679756157753.png
 
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thanks for responding, 98 tacoma 4x, 3.4. for now its a process of elimination. I will add that I removed the battery for about 1 hr. and after hooking it up the engine had no power. would not come up to speed. the other question I have is when you turn the key to the on position, should the fuel pump start, I don't hear it working. when in the start position it pumps gas. thx
 
FWIW, that error code involves signals from a host of sensors all channeled through the ECM.

Unless you have all the diagnostic tools and meters and procedures......I'd suggest a visit to a Toyota mechanic.

I s'pose you could load the part cannon and begin replacing stuff until it works. Take a close look at the list of "Trouble Areas." Not much there for a DIY mechanic to handle.

I suspect the other problems are symptoms of the PO171 code.

If the engine will idle, then the fuel pump is working.
 
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