4.7 going flat when accelerating or under a load

[Ole Buck]

started acting up a few days ago. Got a blinking CEL going down the hwy and then no CEL at all. When you first put her under a load she is as strong as ever but after about an inch of throttle she lays flat starts missing. When checking the codes i get a P0300 multiple cylinder misfire but it will not pinpoint which cylinders are acting up. Clear the codes start it up no codes, drive down the road its doing the same thing and no CEL. Head scratching for sure. Plugs coils injectors sensors cats all less than a year old. No back firing or popping she just want take the fuel. What's new? Fuel pump, cam position sensor. Everything else is less than a year old.

 

[pacofortacos]

Can you run it while on a scanner that can read live sensors? See if it is going lean on you or something?

A MAP sensor that has had the baro read part of it will go super lean and do what you describe, but most that I have seen get to the point that they don't even like to start and idle that well. If you can see what that sensor reading is with the key on, engine off - it should be close to 29 since you near sea level.

 

[Ole Buck]

Yes sir my scanner will show some live data. If that sensor is not showing what you described is the sensor bad or is it doing its job and i should look for what's causing the sensor to do that? Either way thank you for reading my post and trying to help me.

 

[jws123]

Check fuel pressure did you use a oem pump? or a cheapo $80 one? After having many aftermarket cheap ones fail fuel pumps are the only time I really stick to OEM.

 

[Ole Buck]

I went with OEM on everything. So far this is what I have loaded into the parts cannon and fired at the old girl, fuel pump, MAP sensor, cam sensor, crank sensor, throttle position sensor, Idle-Air Control valve along with a few cuss words. OH YEA let me tell you this good one, during my sensor changing madness I put my crank position sensor in the hole where my cam position sensor should have went and she decided that she liked that hole so much better she hung onto it and would not let it go. So I wound up breaking it off and had to remove the valve cover so i could get the broken part out. And it still runs like crap !!!!!!!!!!!!!!!!!!!!!! here is a few screen shots of my new scanner




this is while running

 

[pacofortacos]

That is a really low vacuum at idle, it should be significantly higher.
Other thing I see is spark advance at 110 degree? I can't even see how it can run like that.

Have you checked the grounds? There is a black/blue tracer wire (at least it was that color on cars) that is the sensor ground and it will cause all type of havoc.

 

[LoneWolf3574]

That is a really low vacuum at idle, it should be significantly higher.
Other thing I see is spark advance at 110 degree? I can't even see how it can run like that.

Have you checked the grounds? There is a black/blue tracer wire (at least it was that color on cars) that is the sensor ground and it will cause all type of havoc.

I believe that is 11.0 degrees

 

[pacofortacos]

I believe that is 11.0 degrees

Oh lol, I am very tired.
Like many of the people here, I am of an age where my parents health is becoming an issue. It has been a very long past year and the past month has been the worst yet. Working full time+, taking care of 2 houses, and dealing with their everything just has me wore out.

11 degrees is much better! haha But the manifold vacuum is still low - like it is running pig rich, out of time, or big leak.
Can you put a gauge on the manifold to verify that 12" ? Also note if it is steady or bouncing.

Does this truck have an EGR valve??? If so can it be stuck open? Plugged cats?

 

[Ole Buck]

No EGR on this one and the cats are less than a year old. I do believe that I smelled raw fuel yesterday I will check the manifold pressure. Sorry to hear about your parents I just went through this myself. Both of them getting cancer within 16 months of each other and both passing in less then 18 months. It s a struggle taking care of all that, working and keeping your own family going. My thoughts are with you

 

[pacofortacos]

My condolences on your loss of not just one but both parents so close to each other.

You can rule out the O2 sensors by taking and unplugging all of them (leave them unplugged), clear the computer adaptive memories and start it - the computer will default to mid range, ie. 0.5 volts and all of your short term and long term trims should default to zero.

I think if you can find out why your idle vac. level is so low, you will find your problem.
I am ASSUMING the 12" of MAP vacuum is 12" from 0" with the key on, motor not running.

Do you have a vac. gauge? So you could put 18" of vac on the sensor and make sure the scanner reads 18".

 

[Oliver Closehauf]

Make sure it isn't something stupid like clogged intake or mouse nest in your air box or something keeping your throttle valve from opening all the way.

My dog was going crazy the other day trying to get to something under my Ford Taurus. I finally had to pull it out of the driveway to show here there was nothing there and when I did a freaking ground hog runs out. No idea where it was.

 

[Ole Buck]

Now I have changed the 02 sensors did a hard reset on the PCM cleared the codes and it want hardly pull out of the driveway and throwing ZERO codes. Super dead miss. Sprayed card cleaner around the manifold while engine running zero change. I’m just lost on this one. Checked and rechecked grounds. Is there a way to test my coils with a meter and if so what should I be looking for?

She finally threw this while at idle



How could this just happen at once multiple misfiring? Every plug coil and injector are new and have less than 600 miles on them. Could it be bad gas? I got a small leak detection code right before all of this transpired plus my low fuel light came on.

 

[Ole Buck]

Plugs at 600 miles

 

[jws123]

Have you checked compression? If its running so bad you cant get it out of driveway and showing multiple misfires. Its starting to sound to me like you might have a Intake valve seat issue on one cylinder I have fixed a lot of 4.7s It will make the whole truck run like **** was this truck ever overheated?

 

[RamCares]

Hey Ole Buck,

We see that you have received some great advice from your fellow forum members! However, if these suggestions do not address your concern and you decide to visit your dealer, our team would be happy to offer additional assistance throughout that process! We're available via private message.

Callie
Ram Cares

 

[Ole Buck]

Alright I just put 8 new plugs in. Champion Copper. That truck screamed. Ran wonderfully. Got out and grabbed a coke I let it idle while in the store. Got back and leaving the parking lot it stumbled, not nearly as bad but it did. The CEL flashed a few times and stopped. Then it cleared up, stumbled again and cleared up. Wow

 

[Ole Buck]

Well it’s fixed. I went through all of this just to find out I had an exhaust leak between the headers and the cats on both sides. That was contributing to my rich fuel. But the main culprit was one, single, all by itself ignition coil. I put the meter on them and 7 were exactly the same and one was living in its own world. I could literally throw up. My parts cannon was expensive and wrong. I was completely wrong about the way I went about diagnosing my issues. I did not start at the basics. Air, fuel and spark. I went straight to the fuel and was wrong. Thanks for your assistance people I learned an expensive lesson the past few days.

 

[pacofortacos]

Well it’s fixed. I went through all of this just to find out I had an exhaust leak between the headers and the cats on both sides. That was contributing to my rich fuel. But the main culprit was one, single, all by itself ignition coil. I put the meter on them and 7 were exactly the same and one was living in its own world. I could literally throw up. My parts cannon was expensive and wrong. I was completely wrong about the way I went about diagnosing my issues. I did not start at the basics. Air, fuel and spark. I went straight to the fuel and was wrong. Thanks for your assistance people I learned an expensive lesson the past few days.

Don't beat yourself up to badly, why would you expect a fairly new coil to fail - usually it is either new or old.
If aftermarket coils, I would go to the junk yard and just grab 10 or so OEM coils and use those lol.

Exhaust leak in that area will screw the air fuel up that's for sure, I must have missed you mentioning that you had an exhaust leak earlier.

 

[Ole Buck]

I didn’t mention it. Hell I didn’t know it was there. Let me tell you how I found it. I was doing the Sea Foam treatment where you put the nozzle inside of your intake tube and spray it in while the engine is running. It takes about 5 minutes to do this process. Well before it was over I had white smoke bellowing out of the header flange where it meets the exhaust. It was so loose that I could turn the bolts with my fingers. One good positive thing I learned was how to use a multi meter to check an ignition coil