po300, po171, po174, please help

rossignolskibum · #1 03-24-2008, 07:32 PM

I just purchased a 01 explorer sport trac and have a cheap scanner that is giving me the codes posted. I have replaced wires, plugs, egr, and coil pack and I am still getting the same codes. When I start the vehicle in the morning it wants to stall out and sometimes does. When the truck warms up it runs fine. Any help?????

shorod · #2 03-24-2008, 11:47 PM

Welcome to the forum!

You don't happen to be using a K&N or similar oiled air filter, do you? If "yes," then the problem is likely due to a contaminated MAF sensor. Try cleaning the MAF sensor carefully and see what happens. If you do it right, even if it doesn't fix the codes, it will probably yield increased fuel economy for you.

Additionally, there are quite a few posts on this forum related to the P0171 and P0174 codes. Since I don't like to duplicate information that's already on the forum, and because the Search feature is one that everyone should become familiar with prior to starting a new thread, I invite you to try the "Search this forum" feature from the Explorer forum main page. Try searching for keyword "P0171." And, for your reference, the correct code is P[zero]171.

-Rod

rossignolskibum · #3 03-25-2008, 06:41 PM

Rod,

Thanks for the reply. I did clean the MAF sensor and change the EGR valve now I only have po171 and po174, system to lean bank one and two. From a few conversations that I have had I am told that since I changed the fuel filter and it was full of garbage that my fuel pump is probably bad. I was told to check the fuel pressure and take it from there. Are they correct?

MAF sensors are not cheap either is there any way to tell if it is bad or not?

Thanks........

shorod · #4 03-25-2008, 10:30 PM

That is a reasonable suggestion, that the fuel pump is a problem. Can you hear it running? That's often a sign, if it's audible, that it's starting to fail.

The only real way to tell if the MAF is bad is if you get a code for an intermittant or faulty MAF, or to monitor the readings with the datastream mode of a scan tool (not just a code reader).

-Rod

rossignolskibum · #5 03-30-2008, 06:22 PM

Rod,

Well here is a good one. I had a mechanic hook up one of those expensive scanners to my vehicle and he was running I believe a diagnostics check and about 30 seconds through the test the scanner would kill the engine. Ever hear of such a thing? When it killed the engine it also would not give him any codes?

shorod · #6 03-30-2008, 06:55 PM

I had seen that before on the OBD Fords, but not on the OBD-II vehicles such as your Sport Trac. On the OBD systems, one of the KOER tests is to run the idle speed way down. Sometimes that was low enough to stall the engines. Even then though, the scan tool would not lose communications.

I'm not sure what would cause this on your 2001. I suppose there could be a shorted sensor somewhere that when it gets to that test, it's drawing enough current that it somehow causes the regulators inside the PCM to stop regulating or something crazy like that, but it seems VERY unlikely.

Do you know if the scan tool was running an automated test, or just in datastream?

-Rod

rossignolskibum · #7 03-31-2008, 07:56 PM

Rod,

Good question I will find out.

Thanks!!!!!

rossignolskibum · #8 04-03-2008, 02:14 PM

Here we go again!!!!! Well I solved the problem of the vehicle wanting to stall on inital start up when its cold by replacing the upper and lower intake gaskets they were shot... Vehicle starts great now.....

Now I am getting code p1131 just today and yesterday the vehicle would shake at low RPMs and its telling me cylinder 1 misfire its almost like there are 2 plug wires that are exposed and they are touching but I just installed new plugs and wires...

Any suggestions???????????????????
Thanks a million!

rossignolskibum · #9 04-03-2008, 04:08 PM

I have determined there is no spark to cylinder 1? This just started???

shorod · #10 04-03-2008, 06:04 PM

Did you by chance save the old plug wires so you can put an old wire on for cylinder #1 and see if that causes spark to come back? Or, is the length of that wire similar to another wire so you can swap wires and see if the no spark condition follows the wire or the cylinder?

-Rod

rossignolskibum · #11 04-03-2008, 07:30 PM

What a mess this had been..LOL...Well i purchased a new coil pack 2 weeks ago just cause, and today I determined through trial and error cylinder 1 on the coil pack was shot, replaced it and now everything is fine. Starts great, idols great, now I just hope the check engine light stays off so I can get an emissions test, got 2 weeks to pass...
Thanks for all the help!!!!!!!!!
David

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