2000 Taurus p0171, p0174

[15951]

Any chance it's one or more bad/leaky/clogged fuel injectors? I saw another thread awhile back with similar symptoms, and new injectors cured the problem. My car has similar issues, but the PO171/PO174 has gone away in favor of P2196 and P2198. I've replaced everything but the kitchen sink, and am also leaning towards injectors.

[behlinla]

Originally Posted by fordjunky

I checked the KOEO fuel pressure. If I cycle the key a few times it reads 42 psi. It does start to drop off almost immediately.

If you start at 42 psi what is the pressure reading after sitting 10 minutes (leave the key and scan tool on)?

I don't like the injector idea because your fuel trims are near perfect. You would have to have something like equally leaking fuel injectors on both banks and a vacuum leak that perfectly compensates for the extra leaking injectors.

Your fuel system status is closed, right? If you haven't already, you should monitor the upstream oxygen sensor voltages and confirm they are switching properly at idle and at cruise RPM. Sensors should be hitting 0.1 to 0.8 volts like this:



You were going to look at the idle screw, but DO NOT ADJUST IT unless you're sure somebody messed with it. You should see evidence on the screw (tool marks or lighter exposed threads).

[crackhead]

Originally Posted by fordjunky

Thanks for your help. I really appreciate it.

I don't have access to my scan tool tonight so I will have to reset the Idle speed tomorrow.

I checked the KOEO fuel pressure. If I cycle the key a few times it reads 42 psi. It does start to drop off almost immediately.

If I remember correctly, the pressure should very slowly drop off. About over an hour.
I wounder if the ground for the fuel pump is corroded? This would cause the pump to not run at full voltage when needed. I think it would also allow the pump to bleed off pressure.

[fordjunky]

Well I can't set the idle on my car, no screw.

So I pulled apart the air intake, there is a small gap, what size feeler should fit?

I also replaced the spark plugs, oil and air filter tonight.

Here are the readings....

TPS .90 v
IAC 39-40%
KOEO - 41 psi (2 ignition cycles)
KOER - ~39 psi
RPM - 805-825

The fuel pressure gets to 31 psi after 10 min.

My O2's are cycling between .1 -.8 at idle, I have not driven it in a few days.

Seemed to run pretty well, I will try to actually drive it tomorrow.

[behlinla]

There is a screw on an ear that sticks out on the throttle cable side. I don't have an exact spec for the bore clearance, but my guess would be about 0.005-0.010". IAC duty cycle is better, but your idle was a little high (guessing engine was still warming up). Double check your duty cycle again when the idle gets down to 700 RPM (all electrical accessories off of course), and if it's less than 30% then I would try adjusting the screw to close the throttle more.

Fuel pressure drop isn't real great but I guess it's acceptable.

Just as a thought, I read an article yesterday about a stalling Toyota Camry. It would stall at stoplights and hesitate at stoplights. The cause ended up being a bad coolant temp sensor that was glitching to a really low temp. This will make the engine run really rich all of a sudden. It was very intermittent and the tech was lucky to catch it on the scan tool graph when it did it. So you might consider monitoring the coolant temp PID to make sure it's reading normally.

I'm guessing you cleared your original codes, but if you get another code please post the full freeze-frame data.

[fordjunky]

So I finally got to drive the car a little bit. Everything seems to be working and running correctly.

Thanks everyone for your help.