Hi in there. I am working on my mothers 2004 Mountaineer 4.0 V6 that seems to have a serious problem and she can't give me any details how or when it all started. The truck is giving a PO300,305,306 and 316 codes. The first thing I did is replace the coil pack and it did not help so I took it back. This truck is hard to start, will only do 3000 rpm's in park and will die when you release the gas. I don't smell a bad catalytic converter and its not discolored or anything but I don't really know how to rule it out. Anyone have any ideas where to start?

 

the p0300 code means multiple cylinder missfire. That could be the coil, but you have ruled that out. Next would be the cam sensor, bad or blocked EGR ports, or bad O2 sensor. Normally if its the O2 you will get that code. I might have a tendancy to check the cam sensor and EGR prior to looking into the CAT... but that is a possibility. Hopefully not on a 2004. Got bad gas in your area ??

OBD-II Trouble Code: P0300 Random/Multiple Cylinder Misfire Detected

 

another thought--- the 0316 code tells you the missfire was caught right at startup. Hardly enough time for the CAT to effect it... more like a sensor ???

 

I thought that I would replace the cam sensor 1st. I have been looking for something that tells me where it is and I think that I found it on the driver side valve cover. I read on some forum that their might be two ( one on the back of the engine) but there was some disagreement in the discussion. Does anyone know if its true? On a valve cover seems like kind of a weird place for a cam sensor.

 

Rather than guess and throw part at the problem, have you ever envisioned connecting an OBDII scanner (not a code reader) to the vehicle and checking the live data?????

The 3000rpm is the default when not in gear (normal)....
Miss fires can be triggered by too rich/lean mixture... What is the LTFT???

 

I don't have one (mine says scanner but it doesn't do live data stream) and the truck goes dead as soon as I put it in drive so I can't take it anywhere. I was trying to avoid taking it to the shop on a wrecker.

 

SAD! for $53.00 I have a stand alone full feature scanner....Yours would be a code reader...

Can you recover with foot on throttle when engaging D?
Sounds like you have a torque converter lockup problem, if it is killed as soon as drive is selected. Philip

 

If they are that cheap I will get one tomorrow. As far as your question goes...you can pat the accelerator and it makes no difference in drive. It still goes dead. It is not an instant fast dead like it is locking up...it just acts like it just doesn't have any power left and dies. Actually one time today it would engage in drive and reverse but the next time I tried it, it would not. Keep in mind though, it is missing real bad in park too.

 

When was the last time the plugs were changed??
Have you performed a fuel pressure system test???
how about a compression test, WARM, DRY/WET, WOT and fully charged battery, fuel and spark disabled Philip

 

Well s**t. I had already changed out the #5 and 6 plugs because that is where the misfire is. Today I pulled the rest of the plugs just to check them and guess what? Water in # 2. I will start tearing it down today. I just hope the head is not cracked or warped. Really strange that there were no codes on #2. I also believe that I may still have a secondary problem but first things first.

 

Be fore you tear it apart, do a compression ....or, a leak down test.
The leak may be restricted to an intake.... Philip

 

I had already pulled intake and there is moisture in every port. What could this mean?

 

Compression test makes no since to me other that this thing must have run real hot...probably cracked heads. Results are Cyl #1=30 lbs, #2=90, #3=120, #4=150, #5=50 and #6=90. Any thoughts?

 

Check carefully, there is a leak in the intake manifold or gaskets.... Philip

 

Now is the time to do the Leak Down test, if the heads are cracked it will show... Philip