2001 5.4 Super Crew..engine flawless til early '05, then when towing 4600 lbs uphill sounds like valves ''floating'' or spark-plug ''knock''...had 1st rate tech (not Ford) replace all spark-plugs and some sensors...runs better, but same noise...plus now does it when accelerate at Interstate speeds (not towing)...upgrade to 89 octane and noise goes away...
Have been told sensor in air-intake may be bad...
Anybody got the scoop on what's REALLY happenin'?...

 

I have a 1998 f-150 2wd 4.6L. For the past year ive noticed that when driving at highway speeds under normal driving things are good, BUT when you give it some gas you can hear what sounds like the lifters or something ratteling or ticking. Doesnt seem to affect power, but sounds awful . Just had a tune up, fuel system cleaned and new fuel filter a few weeks ago. Truck has @111,000 miles. 93 Octane gas seems to make it quiter and less sometimes it goes away. ANY IDEAS???????????

I had a FULL tune up and they said all looked good. 93 Octane practically makes the noise go away. If you find anything out let me know!!
[U]tlratcliffe@hotmail.com[/U]

 

Does your '98 have a sensor in the air-intake after the air-filter?...any wire(s) comin' outta the duct that would indicate the presence of a sensor?...

 

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If that ticking noise only occurs at low rpms and lots of throttle, then it's probably spark nock. it is a form of pre-ignition. Anyway, upgrading to a higher octane gas should prevent this from happening. I don't know if there is a cure for it though. I've had some trucks that did it and some that didn't. My girlfriend's 2000 ranger does it but my 97 f-150 doesn't. My dad's v10 ford does it on 87 octane only. put 89 in it and it shuts up. go figure.

 

That's the BUMMER about this...this motor used to be PERFECT...then in erly '05 noise started...something has changed...something is malfunctioning and I'd sure like to get to the solution...

 

I'd say you are getting knock from build up of head/valve/piston carbon. You may want to seafoam it. Seach for seafoam here for more ideas. Pre-ignition
can be caused by carbon glowing or the increase in compression due to volume of carbon. Higher octane burns slower/harder and resists the pre-ignition. Let us know

 

I had the same type of problem. Pinging under load such as towing with acceleration or just going up a hill with a fair amount of acceleration. Took out my MAF sensor located in air intake (required a security type screw driver to remove it that I got at Sears). I sprayed it very liberally with CRC QD (quick dry) electrical cleaner. The thin wires did appear to have a dark coloring to them that seemed to really shine up after cleaning. Pinging is totally gone. Some people clean it while still attached to the intake.

 

Not quite sure what seafoam is or where to get some. Any info would be great!!

 

https://www.f150online.com/forums/sh...hlight=seafoam


Search....... seafoam in this group. Use search.....

Everything you would ever want to know (and then some)


It's a lube/solvent kinda stuff. I have used water to break up carbon, but many swear by this stuff. I'm thinking of a direct attack (drizzle into vacuum line ) for max effect (smoke cloud) into warm engine and stop, wait 15min or so then re-start . May want to change oil soon after.

Got mine at Advance Auto about $5 per pourable can.

 

Tom, thanks for the tip on the MAF sensor...will try CRC QD...it'll be nice if it turns out that easy a fix!!...

Seafoam is a CARBON BUSTER...generally used in 2-stroke outboards, but don't know a reason why not 4-strokers