Jonathan Malick Jr.

Hi, I am dire need of help. I have a 1997 Ford f150 with a 5.4L triton motor. The truck idles fine but once it is under load it shudders and misfires. I reset the computer the other day and it ran great with the factory fuel and air settings, but once it started pulling in the data from all the other sensors it started acting up again. Please help!!

BareBonesXL

Is the Serve Engine Soon light (aka CEL) on? Are there codes? When you say it "ran great" does that mean you were able to drive it around normally until it went bad again?

The more details the better. All you've described so far is a truck that runs better after resetting the KAM. Add time to your descriptions also, like how long it "ran great", how long you've had the truck, how long it ran well before it started running poorly. Time is important.

techrep

iTrader: (1)

when was the last plug change ? shudders under load and mis-fires...

Jonathan Malick Jr.

No the CEL is not on Also yes, when it ran great I was meaning it ran like it should. And it only ran great for about 2 minutes then that it when it started acting up. I've had the truck for about 2 years and it ran like it should up until a month ago. Also I just replaced the plugs.

BareBonesXL

Did you replace the plugs to try to solve the problem or did the problem happen after you replaced the plugs? Sequence of actions matters too. Sorry. Writing is hard to get right but the words you post are all anybody out here has to look at.

Are you sure it wasn't running right because it was cold, not because you reset the KAM? Or because fuel pressure was up from the priming cycle. Try restarting it a few times to see if anything consistent happens. Reset the KAM a few times and see if it does exactly the same thing every time.

Kind of sounds like a fuel supply problem. Fuel pump or regulator. Fuel pressure would be good to know.

Jonathan Malick Jr.

No I completely understand. I replaced the plugs to try and fix the problem, but didn't make anything better. The fuel is at 34 psi. Also every time I reset the KAM either hot or cold it still did the same thing, ran great the acted up when it start using the data from the sensors.

BareBonesXL

Do you have a code reader? There's probably a pending code. They don't go full code until so many cycles or so much time passes.

Maybe it's those cam phasers. Good luck. That's all I know.

https://www.google.com/search?source...60.9YEyqS6gUkw

Jonathan Malick Jr.

Unfortunately there are no pending codes, and ok thank you though.

DarrinT04

if you reset the computer a few days ago then maybe it hasn't had enough time and cycles to throw a code

Jbrew

Wrong forum, or your confused. Yea, these trucks don't know what a cam phaser is.
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OP, what are you talking about when you say factory settings, are you using a tuner ?

Yea, don't reset the KAM anymore, not before you scan it. You have low grade misfire problems. These problems do not illuminate the CEL, but they do produce a DTC in the KAM once the misfire monitor count is high enough. So you need to scan it regardless of illumination, don't reset.

Replace coils with Motorcraft or Denso coils. Denso produces Motorcraft, same coils.