Cel 173 & 176

[jcwdallas]

I have a 1994 Ford Ranger 4.0L with codes 173 & 176. (System rich bank 1, and system lean bank 2.) Both O2 sensors bad? Bad fuel pressure regulator? Plugs and wires bad? All of the above? The truck cuts out at low speeds, but when I floor it, it will pick up power big time. Where should I go first?

 

[FR-425]

KOEO or KOER?

These codes have two fault states depending on the type of test run.

176 KOER = insufficient TP change during No o2 check.
While 176 KOEO indicates always lean.

If your CEL is on and you pull the codes after the drive cycle you would have 176 "lean"

If you are getting both lean and rich faults; the fuel delivery is jumping around.

If that's the case I'd start with looking at FPR, and for leaky injectors.

The TPS can cause erratic injector action, and is most likely the cause.

So, very first thing is to replace that $50 headache.