I have a 2000 ford ranger with the 2.5 and a manual trans 240K miles. 2weeks ago it kicked a PO171 with a PO301 pending code. It runs like the title says at an idle when cold but around 1500 rpm it tends to run like a scalded cat!

Heres a run down on what ive done so far: plugs, wires, air and fuel filter, 4 new injectors (just cuz i had them) it runs 62 psi for fuel pressure. I checked for vacuum leaks (3 cans worth) and cant find any. not that it matters but the dpfe was replaced 2 months ago.

The engine is the stocker so i'm gonna try a compression test tomorow just to check things. It does have the stock cat on it still and a minor exhaust leak. Do you think the exhaust leak could throw these codes? Its by the manifold or egr tube i'm not sure.

I'm just running outta ideas. Thinking about it has almost worn me down. Any fresh ideas out there? I would appreciate it

 

Found this when I did a search of your one code and owner had same engine/year of Ranger. Can't guarantee this would fix your problem but worth checking out to eliminate it. If you haven't done it yet try cleaning the MAF sensor and replace the gas filter to rule them out.


Re: P0171.....looking for vacuum leak
I finally got closure on this back in May but forgot to post it.

Broke the problem down and searched it out like this.....

Running lean (P0171) is caused by either a) too much air, or b) too little fuel, or c) sensor issues.

So I did my searching from easiest/cheapest first then to more complicated/expensive.....

- First I made sure all maintenance/tuneup stuff was up to date.
- Then I searched for vacuum leaks (too much air) but didnt find any.
- Then I got a pressure gauge and checked the fuel pressure on the rail (too little fuel). Bingo! There was only 30 lbs and it should have been 64 +/-8. So I did 3 things in this order 1) tested the fuel damper, it was OK, 2) tested the voltage at the fuel pump, it was OK, so that meant that the fuel pump was bad, 3) so I replaced it.

After replacing the pump the truck runs near perfect, and has for 3 months.

By the way, I removed the bed to get to the pump. There are only 6 bolts, two filler neck hoses, and one electric wire plug to mess with. And with 6 mins of help from my trusty neighbor (3 to move the bed to the yard and and hour later, 3 more mins to put it back on) the process was pretty easy!
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2000 Ranger XLT, Ext Cab, 4x2, 2.5L 4 cyl, 5spd man

 

Here is a link on the PO301 code

OBD-II Trouble Code: P0301 Cylinder 1 One Misfire Detected

 

I didn't get around to running a compression test on it today. I completely spaced out and forgot about the MAF sensor... oops. But it did run through my head that maybe the exhaust leak before the o2 sensor could throw it off. Does this sound right? Or even possible? My 01 super duty didn't do much when it leaked at the manifold but its also not a 4 cylinder.

Anyone with an opinion on this?

 

Just thought i would follow up on my ordeal. After cleaning the MAF and running a compression test and verifying that those where in good shape i decided to test the o2 sensors. They are working just fine so i hooked up the v-tec and decided to watch the sensors work. The rear sensor seemed to be lazy... The numbers didn't seem to match. That led me to beleive that the Cat was plugged. So with a little chopping cutting and inspection by golly the Cat was junk!!! So against my better judgement i actually put one back on from a vic. Now she runs like a champ!