2003 Ford F-150 puttering

TALLTOMMY1188

MEMBER
2003 FORD F-150
6 CYL
2WD
AUTOMATIC
120,000 MILES

Hey guys, my truck has been running great up until about a month ago. I had the battery replaced and now as I drive it putters a bit at random times while applying the gas. Also when going from a stopped position as I accelerate the engine makes a knocking noise. Do you have any ideas on what this could be? And how much that repair usually is?

5 Replies

JACOBANDNICKOLAS

MECHANIC
108,192 POSTS

Has the check engine light come on? Have you checked fuel pump pressure or for vacuum leaks? Finally, the knock has me concerned. Does it only do it when you accelerate? Does it sound low in the engine or more like valve ping?

Let me know.
Joe

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Monday, January 11th, 2010 AT 10:17 AM

F150SCOTT

MEMBER
2 POSTS

I am having the same issue as Tommy. I have tried a few repairs myself but nothing seems to make the knocking noise go away. I have replaced all the spark plugs and I still get an error code that there is a misfire at cylinder 1. I also got an error mesage about the crank sensor.

Jacob- thanks for your help. The knocking noise only happens when I accelerate and sounds like a valve ping. Before I repalce the fuel pump or the sensor I was hoping you could provide some additional info. Thanks for your respoinse and help.

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Tuesday, January 19th, 2010 AT 12:25 PM

JACOBANDNICKOLAS

MECHANIC
108,192 POSTS

Have you tried replacing the knock sensor? It sounds like a timing issue.

Let me know.

Joe

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Tuesday, January 19th, 2010 AT 1:44 PM

F150SCOTT

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2 POSTS

I have not heard of a knock sensor but I will do some research. Thanks for the help

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Friday, January 22nd, 2010 AT 10:50 AM

JACOBANDNICKOLAS

MECHANIC
108,192 POSTS

Here is the definition of a knock sensor that I got for you. Also, there is a picture of its location on the 6 cylender after it. Check it out and see if could be what you are dealing with or causing the problem for you.

The operation of the Knock Sensor (KS) is to monitor preignition or "engine knocks" and send the signal to the PCM. The PCM responds by adjusting ignition timing until the "knocks" stop. The sensor works by generating a signal produced by the frequency of the knock as recorded by the piezoelectric ceramic disc inside the KS. The disc absorbs the shock waves from the knocks and exerts a pressure on the metal diaphragm inside the KS. This compresses the crystals inside the disc and the disc generates a voltage signal proportional to the frequency of the knocks ranging from zero to 1 volt.

The KS is a tuned accelerometer on the engine which converts engine vibration to an electrical signal. The PCM uses this signal to determine the presence of engine knock and to retard spark timing.