big-o

Is there a particular thread that you can direct me to explaining how to test the o2 sensor/circuitry?

A little update here, I ordered the o2 sensors from Rock Auto and saved good $ right there. In preparation to changing these sensors I sprayed wd40 on the threads to hasten the removal of the old sensors and what do you think occurred? The error code went away as the spray acted to facilitate a good ground and although the code is gone, I will at my earliest time change the sensor anyway. But it is something others may want to keep in mind.

UKblue150

First off. Great work on these details on the first page.

I have a 2003 5.4, throwing the EVAP large leak and small leak codes. Talking to local mechanics, they lean towards changing the charcoal canister. Some sites say the only issue is the valve needing replaced. From my findings there can be a $50-$300 price range on repairing these codes/issues.

I have located an related article however the owner removed the whole bed to replace the canister which is under the mid bed cross member.

What has been the most common issues/repair method regarding the EVAP system leak codes.

jcewl93

Hi, I have a 97 F150 4.6L 137K setting P0401 EGR flow insufficient, and P1151 Lack of HO2S21 Switches-sensor indicates lean. I had a hard misfire on #6, so the O2S is probably clogged. I have replaced the EGR valve (which wasn't caked with carbon) to no avail, and the EGR tube did not seem clogged. The code-setting is intermittent. I have checked the EVR this morning, and it is good per your test. I tested the DPFE and have about 5VDC with the engine warm 180 deg F. I decided to check output with the sensor connected and got intermittent voltage on the ECM output/GRD of 0 to 0.9 VDC. Is this indicative of a bad sensor and the source of my problems?

Also, Advance Auto lists a EGR Valve Sensor for my truck that I don't find in your write-up: http://shop.advanceautoparts.com/p/b...631/20470049-P

boatguy

I've been trying for the last month to chase down an intermittent miss in my '03 5.4. Truck runs fine until it gets warm, could be fifteen miles, could be fifty - then starts to balk and miss sometimes a lot sometimes not. Curiously, the miss will also sometimes just go away on its own after a few miles of acting up. Other trips it will continue to get worse to the end, although it hasn't completely quit running yet.
I've had it into the dealership for analysis, they gave me a laundry list of maintenance items - came to over $1,000 - but couldn't tell me what was causing the problem.
I've cleaned the MAF sensor (twice) renewed most of the grounds around the PCM, checked relays and am currently halfway through changing out 1 COP at a time, so far no change. The baffling thing is the lack of consistency in the symptoms - no special speed, doesn't matter if it's under load or not and can happen sooner or later. Last time it happened it threw a code so I went to Auto Zone and got it read - says possible coil or injector and the code was for the O2 sensor. Anyone have a similar experience?
Thanks for all the info on this forum -

pon55

Yup, got the same thing. Working on it.

Jbrew

Why don't you start a new thread ? Sounds like a low grade misfire. Those can be tricky , but there are ways to determine and/or narrow it down to the cylinder. From there it's a fairly easy process of illumination.

Swingback

Just joined because of this post keep up the good work I was looking around for problems I'm having with my 97 4x4 and came across this so I'm here to stay now hopefully I will find out what's going on with my truck it has a miss, back fires sounds like through the intake and exhaust miss is at low idle and at higher rpms. New plugs and coils egr cleaned and all

texisman

Could someone please explain this a little more. I don't understand how testing the harness side can determine that the DPFE sensor is bad. Wouldn't you have to actually test the sensor itself or do you leave the harness plugged in and probe the terminal VREF?

Also it goes on to say;

but in the previous paragraph is says, "With the ignition key on (engine not running), ".

Thanks.

wilson84

Any suggestions on iat sensor before i take it to get pcm reflashed not getting the 5 volys to plug I jumped the ray red wire to neg termanil on battery it reads 12+ volts but when I turn key on and jum the gray to postive terminal I only get around.012 volts

willfortier

my 02 f150 w/5.4 motor was in accident and the passenger front was smashed in good . ever since then if motor is cold and u drive it its fine after about 10 miles its starts to stumble and get real rough and lot of vibration when I come to a stop rough idle. so could it just be coincidence and just maybe a fuel filter problem. or ?