Rattle when acclerating
 

I've got a 4dr 2009 Sahara with 35s on a teraflex 2.5 coil and shock lift. I've noticed a rattle sound when accelerating hard to highway speed or climbing on local roads. Had one suggestion that it could be the wire for the speedometer.

Any ideas?

Not sure if this is the same as what I had but check your heat shield that is stitch welded to your crossover exhaust pipe, the pipe that goes from passenger side to drivers side right behind the engine. Make sure one of the welds is not broken. Mine would rattle when I accelerated but stop when speed was constant.

Are you sure it is a rattle, or is it spark knock (pinging)? If it is a rattle, it is probably a heat shield

Ive often had rocks get lodged inbetween my exhaust crossover and my factory skid that would cause a rattle on acceleration...mabey something to look into, also heat shields as said before

x2 - had the same issue, the welds go bad... i just clamped it. all better now :)

x3 - I put hose clamps at each of the weld points on that heat shield, and it quieted right down.

FYI, you might not see a broken weld when you look for it - mine looked fine and didn't feel loose, but I tried the hose clamp fix anyway at a friend's suggestion, and it worked. Must have been just a tiny crack in one of the welds, but big enough to allow it to vibrate under acceleration.

Check all your heat shields including manifold, the ones on the floorboards under the cab and the ones by the motor mounts. I had one loosen under the cab and one bend on the motor mount that both made a noise until I lost the one under the floorboards and bent the one on the motor mount out of the way.

Thanks all, I'm going to check on those suggestions this afternoon and will update. Thanks

I just had a shop install my skidrow engine and tranny skid while also installing a sleeve and gusset kit. Since they had to bend a bracket while fidgeting with the exhaust, is it possible they broke the stitch welds on the heat manifold like you guys are talking about? I'm all the sudden hsaring a rattling while I am reversing or while I am accelerating at a light... it doesn't happen all the time, but it has been happening since the night of install. Had them mess with the exhaust today to get it to stop but still seems to be making noise. What should I look for exactly?

It's most Likely sparknock, try upgrading to a tank of 89 octane and see if it goes a way.