The engine light came again today and it's the same P0307 code, misfire lucky 7, I drove the truck for a few hours and I noticed before the light came on the engine at idle was a bit bouncy. What do I check or replace next?

 

At what point do you decide to stop throwing guesswork parts at it and take it to a dealer? By my count you're down at least 8 plugs, 8 coils, 2 injectors, 1 Snap-On compression adapter, and a ton of time.

 

Dragon, I obviously like doing this so time is a moot point - I only bought 2 fuel injectors, I needed to do the plugs regardless but you are right about the purchase of that Snap-on tool, that burns me up. I am however a little amused that none of the senior members have given me any feedback on the correct adapter for the compression test, I mean this is one of the most popular motors in the ford truck family.

 

"Senior member" doesn't necessarily mean "compression test expert". It has to do with number of posts on the forum. I, as a senior member, have never done a compression test, nor needed one on any of my trucks thus far.

BTW, it's "moot" point. Mute means the point is soundless, not irrelevant.

Good luck with your code.

 

I haven’t done a compression test in...decades. I had a ‘67 F100 with a 240 straight six back in 2001 that needed a compression test. That was the last time I did one.

 

Ditto. My two compression gauges have the rubber end and would never work on the 5.0.

 

I have a huge box of Snap On tools sitting in my garage. Three Compression gauges a 45 and a straight push on and 1 thread on with the 2 old standard sae threads. However I stopped doing professional mechanical in 1999. Stopped buying new tools after OBD1 because it was no longer worth while for me and stopped doing oil changes in 2007. Why you might ask is because I was absolutely burnt out. I went to work as a Security officer for the State of Texas for 5 years then took on a job as The Machine Shop Supervisor in the same facility. The State furnished a ll tools. My ford dealer was doing Free oil changes for 30,000 miles. I traded vehicles by then most of the time anyway. And now I have been retired for the second
Bottom line is I don't have a clue what it takes to reach these new engines for a compression test, and really don't want to. I don't have the ability or stamina to climb up and around to do so. I do check the oil , as I can just reach the dipstick. The dealer isn't doing Free oil changes now but It isn't that much more than I can buy the materials for and rotated the wheels now for $15.00 Heck I wouldn't rotate the wheels for that 20 years ago.
TJ

 

I believe I have already described most of the causes of a P030x code.
If your Snap-On can display a signal showing the coil firing voltage pulses assuming you have the correct cabling, it would show the loss of voltage on that cylinder if that is the cause.
It then would put the failure as electrical in nature.
Otherwise, a random failure usually would not be thought of as a mechanical failure that comes and goes, but anything in possible.
You found out that having a Scanner of any level does not guarantee success if there is little experience behind interpreting what it shows.
.
Issue:
1. A drivability.
2. Dash alarm or indication.
3. A code to back it up.
4. What does the code indicate?
5. What to check out by scanning checks with tools.
6. Verifying the cause.
7. Doing the repair and checking again for the same failure or drive cycle long enough the be sure the repair was the cause.
.
Doing owner upkeep is a different story as to ability, tools to test with and parts to make the repairs.
It's all a perspective on expectations, experience, diagnostic and support tools as to success.
Even dealer service short cuts some of the above and does a hope and guess routine that causes a comeback for the same issues over again.
Modern vehicle technology has about run ahead of owner capability to even the point they don't know all the features the vehicle has been equipped with let alone different model levels within the same line.
I'm not trying to be insultive but bring a different look at what may be the case for everyone who reads this.
One example is I have been tracking my 5L passing of some not a lot of oil from the dip stick full mark.
Over 20k miles, a pattern is emerging that is far different than is being talked about on these forums and certainly would be disagreed with if I were to explain it without enough proof over time. Here again, it takes knowledge of the difference in how the motor was designed, the motives behind it, and a possible decisions but cannot prove it at this point.
Enough for now but just to offer some other points that are not being used as part of the overall picture.
Bring up phases like WHY this and that, my other vehicles did not, the design is faulty etc does not cut it and is a narrow minded approach.
If one does not like a vehicle, get one that is perfect in your mind. I believe you will look a long time to find one.

 

The dealer knows that cheap oil changes and rotations sell cars. How many have walked around the lot and started a trade deal before the oil change was done? Quite a few I bet.

 

I'm not sure you are responding to the correct thread?

My code is P0307 - misfire #7

The snapon tool referred to in the thread is a compression tester adapter meant to screw into the sparkplug location that doesn't fit and not because its not long enough.

Is the scanner your referring to an OBII scanner?

I never complained about the design, I just want to diagnose the problem.

 

I must have entered the twilight zone.

 

.
Code P030x is the correct 4 DIGIT format.
X = the cylinder number.
In your case it is #7 or P0307.
If it were a V10 motor, the code would be P0310 for cylinder 10, if that cylinder was misfiring.
(If) your code was P0357, The Coil circuit for that cylinder has a fault.

See what I mean about interpreting the codes?
Codes 035x and 030x are totally different in meaning, but both would be a misfire as in 'no spark' or slow rotation time for two different reasons.
These two different formats are detected by two different software sensing programs.
1. The 30x misfire is detected by measuring Crankshaft rotation time.
2. The 35x is an electrical monitor in the computer looking at each coil performance.
See how different they are?
Good luck.

 

Here I am 6 months later with the same problem, the vehicle throws a misfire code P037 - cylinder 7. I have put another 14,000 miles on the truck since my last post and not much has changed, no better and no worse. I can feel when it's misfiring and when it's not and it is intermittent and it was only at idle or in park in the beginning but in the last month the misfire is very noticeable in reverse and the check engine light starts blinking and then disappears when I put it back into drive.

I took it to my local mechanic to have them do the compression check, he said all cylinders were in the acceptable range but didn't have the numbers to share with me. He said he couldn't find a vacuum leak and is at a loss as to why it's misfiring, bye bye $200.00

I purchased a smoke tester and I couldn't identify a vacuum leak. I recently purchased a nice Ancel car scanner in an attempt to solve this mystery. The problem is I don't know what most of the results of these tests mean. What the scanner did tell me that I could understand is the engine continually misfires any time the engine idles below 600 rpms, in fact it always reads "Engine RPM at time of last misfire" 596 rpm.
Can someone point me to the right scan tests that can be performed to help narrow down where the fault is? As an example one of the data stream tests "Variable CAM Timing Bank 2 Exhaust status" "No Fault" - but it doesn't show me any results for Bank1? Why is it not reading Bank 1?

 

He did a compression check on all 8 cylinders? Pulled all those plugs? If I was going to to that work, I would have put new ones in, making sure they were gapped to spec prior to installing them. All new boots on every coil, then try a new one on 7. Or swap 7 with another and see of the misfire moves to where 7’s old coil was moved to. Make sure you use a Motorcraft coil f you change one or all of them. No aftermarket coil is near as good. Don’t even bother with Chinese crap from Amazon or eBay.

 

CEL blinking in reverse not in drive or neutral!
Right there ID's the issue.
Blinking CEL tells you that ignition failed on that cylinder. Blinking tells you the cat on that bank is subject to burning fuel in the cat and causing damage to the Cat.
In reverse highly suggests an electrical connection/wire/harness issue due to the motor rocking in it's mounts.
The intermittent is from the same cause. Movement!