I searched the previous threads but didn't really find anything like my truck's symptoms...

In fourth gear, under light load (2500 - 3500 rpm), I hear a clatter/ticking sound that sounds like it's under the hood (but it's hard to tell).

Mods are 90mm MAF, lower pulley and chip.

Does anybody have any new info on this?

 

that is most likely PINGING...i would get ahold of your chip tuner and have them reburn your ship as soon as possible. i bet if you put a couple gallons of race gas in the ping would disapear ..

 

I'd do that, but he wants $100 to re-burn it. Maybe I'll get a different tuner's chip.

Also, why would detonation just start out of the blue? I've burned over half of the tank without hearing it, so it's probably not a bad batch of fuel either.

 

Madhouse-My 01 and my buddies 01 do the same thing in cooler weather!! It doesnt seem to be a problem in warm weather. But @ 65 deg. or cooler while lugging in OD, if you ease into about half throttle, you can hear ours rattle. I put a can of the NOS racing octane boost in a tank of gas and the rattling stopped. Its susposed to increase your octane up to 7 points. Kinda high
@ $11.00 a can though! My buds 01 is stock and mine has upper and lower pullies....doesnt matter, they both rattle!

 

Thanks for the info Skank Dog. I never even considered the temperature.

 

Skank Dog -

You asked me if mine did it this weekend and I said no. After the reburn I now say yes. I had to put some 91 Octane in it on the road home to KS and it started immediately.

Its definitely pinging and there are a couple of reasons. The more aggressive timing will cause pre-detonation and the cooler air changes A/F ratios. Cooler air is more dense so you need more fuel to keep the same ratio. The warm weather program might be a little lean for us when it gets cold.

The other factor is the gas itself. There apparently are little differences in the way the stuff is refined and blended across the country. An east coast tuner is going to be familiar with the gas in his area. I heard someone say that Jim had to tune a little different for the gas down in Houston.

I've got back to good 92 octane and I'll see how it goes. If I need to I'll get some 100 octane pump gas that is $3.75/gallon.
BTW, the reburn (when I had 93 octane) pulley, and throttle body made a HUGE difference. Can't wait to get to the dyno and see where I'm at.

Nice meeting you and stay in touch.