Ford ranger p0301

Hello everyone, I have a 1997 ford ranger 2.3 with 178,000 that seems to have a intermediate misfire on cylinder one. It will only misfire at idle after a few minutes of running, after it is warmed up it runs great. When looking at my scan tool it will usually have a coolent temperature that is in a range of 120 to 150 F. I have replaced the Spark plugs and wires, temp sensors, coil pack have been tested and are in good working order, and replaced both O2 sensors. If anyone has any recommendations I would really appreciate it.

You've already replaced the parts that are most failure
prone. Only thing I can suggest is to take a look at the
number 1 fuel injector. Also the electrical plug for the
injector. Maybe remove it and spray with WD-40 and
re-attach...

..^^^ Good points..

..I am hoping he replaced all 8 plugs and 8 wires..It would not be the first time someone had only replaced the bottom 4 and came here for further help.

Ok great thanks for the advice. I replaced all 8 of them, which was a real pain!
I'v been wanting to swap the fuel injectors to to see if code changes but it's looking like I will have to take the intake manifold to get access to fuel rail. I will try to swap it this weekend and will let you know if it changes.

...This might be of help..

http://www.explorerforum.com/forums/showthread.php?t=362910&highlight=injector

...any updates on this?

Replaced cylinder 1's fuel injector with one from a junk yard last Saturday. With the cold weather it hasn't thrown a code yet but it does sometimes idle funny at times. Will let you know when it warms up and see if it throws the same code.

Still no cylinder one misfire. In my opinion I don't think replacing injector 1 changed anything. In fact I think it's getting worse as of now it is starting to die out and have trouble starting. If anyone has any suggestions/opinions on what I should do next that be great.

...So..you are no longer getting a p0301 code after swapping in the #1 injector?

As of right now yes it hasn't
But I think it will give a code again once it warms up in Ohio.
Since it does it more at curtain temps(mainly warmer temps).

I would say clogged fuel filter.

That's what I would of said
Back in September though I replaced the fuel filter

In the absence of any codes, the next thing to look at
would be the fuel pressure.

Last winter I changed a Ranger fuel pump with only
60K miles on it. The brushes tend to wear out on the
pumps, making for erratic pressures at different times.

Ok
I will check the fuel pressure in the next couple days and will post what I find

Finally threw a code since its been warming up now. Threw the same p0301 code again. Sometimes the engine light flashes now when it goes into another one of its episodes. Put a fuel pressure guage on it when it was doing it's misfire had a constant 30 psi. This is really driving me crazy! Any thoughts?

..Get it checked by someone with a scanner like a mechanic as there will be other codes if its flashing..

Ok yea I'll see if I can get a hold of one that is more advanced then mine.
I'll let you know what it shows. Should be able to use it over the weekend.
Hopefully I find something that can explain what's happening.

Haven't had a chance to take it to get it diagnosed but just wanted to add that the car is now shutting off and having issues starting after it shuts off if the car is warming up when you are accelerating and you let go of the throtal and coast
Definitely a temp issue I have noticed it will act up again while your driving if you accelerate hard.

Have a throwout bearing that is going out on my ranger
Was wondering how long those bearings last once they start to make noise