I've searched on here and a couple other forums for the last couple of days and still can't figure out this rattling noise sounds a lot like the marbles in a coffee can descriptions.

Truck is a 2007 5.4L 4x4 SCREW, 45,000 miles, AF1 intake, Efans, ASP UDP, VMP Tuned 87 perf, MC oil and filters (around 2000 miles on the oil). No codes except for the two from the Efans.

Noise is a rattle almost like predetenation, only happens with a light to moderate acceleration on the upshift between 45-60 MPH almost always about 55 1500-2000 RPM, for about 5 to 10 seconds probably . Let off the gas it goes away immediately, more on the gas goes away immediately. I think the truck has always done it but I was in Korea for the last three years and rarely got over 45MPH. I know it was not this bad when I was in the states before.

I don't think it's gas I just did 2 tanks of chevron mid grade and 1 premium no change.

Maybe the tune but I don't think so because it does it on all three 92 perf, 87 perf, and 87 tow, plus I tried the canned sct tunes. Did it with all 4 tunes I tried but seemed a little less on the tow tune. But still there I haven't played with the timing yet because I don't know what I'm doing.

Don't think it's the timing chain or the cam phasers because it only does it in the conditions listed above and from what I understand those are more of an all the time thing or more of a start up(but I might be wrong).

The only other thing I could come up with would be the IWE I don't get the clunk when putting it in or taking it out of 4wd. I did do a vac test, and I'm getting ready to go try and drive it in 4wd to see if it still does it.

Just looking to see if anyone has had this or if there's something I haven't tried yet. Thanks in advance

 

Are your tunes written for that SPECIFIC intake? If not, you are running excessively lean and it *IS* spark knock. Do NOT run the canned tunes, that just makes it worse.

Contact VMP and get your tunes fixed before you burn your valves.

 

Thanks for the reply. Yes Justin confirmed the tunes were written for the intake and I went through several tunes with him before I went to Korea and these are by far the best of the bunch but still may not be quite right. I know the canned tunes are junk but I was trying to narrow it down a little. I've had these tunes for about five years so I think I'm going to try 5star and see if it makes it any better.

Would a lean condition not populate a code? Or is it intermittent enough that the truck thinks it fixed the problem? Is it common for spark knock to be that specific? Thanks again for taking the time.

 

Thank you for the background.

Next step should be to remove the tunes altogether and reload the stock tune.

The reason I'm thinking lean is this - it's making the noise at the point in the fuel map where it's running leanest by design. Those exact conditions are where low grade misfires occur when the spark plugs and/or coils are getting weak.

3 things can cause spark knock - timing too advanced, fuel too lean causing high combustion chamber temperatures, and combustion chamber deposits effectively raising the compression ratio and causing localized hot spots.

For troubleshooting, do you still have the stock intake and MAF?

 

I will try to put the stock intake on this weekend and put it back on the stock tune if I have time. For the time being I shouldn't be driving in that range until then plus as long as the weather stays nice I'll ride the motorcycle. Thanks for the advice, it's greatly appreciated.