Pulsating over 3500K rpm
 

Setting in the driveway tonight I couldn't get it to rev over 3500 without surging 500-800rpm. No matter now I tried to get the revs above 3500, it wouldn't go. It drives OK, but I noticed a big drop in fuel mileage the last tank. Going from a normal 19mpg to 13.5 tells me it's not normal.

Sounds/feels like a rev-limiter, but I've been able to get the tach up a lot higher setting still before. Accelerates fine normally

FWIW, 2006 Sport, 4x4, 4.0L automatic. Just under 52K. No codes thrown, but I'll check it tomorrow on the way to work.

So, does the auto even have a rev limiter? Would it all of a sudden START working, since I'm rev'd a bit higher than that before. Hoping for a bad tank of gas, but any mechanical suggestions I can look at as I burn through the new tank?

its a rev limiter you bad mileage is from revving the piss out of it.

You speak of revving it passed 3500 thats bad for mileage also dont rev passed 3500. I get 19mpg if i dont rev over 3000

why would it be limiting him to 3500 rpms?

In park and neutral so you don't blow the engine up

Wow....guess they don't trust the vehicle owners to do anything, do they?! I've been pretty sure I've had it higher than 3500 setting still before, just didn't seem right that it only started today. Guess I wasn't going as high as I thought I was. No chance of 'blowing the carbon out of it' is there :15:

My bad mileage is from several things, at least several things I'm mostly sure of:
I usually don't get above 35mph the entire way to work. A whopping 8mi. of deer and school bus infested back roads.
I'm thinking of the last time I got gas, I was pointed downhill....and I always park uphill when I get gas buy 'my' pump was occupied. Didn't take the usual 16.X gal to the clicking off of the pump.
With the temps coming down, I've used the remote start more, so idling for 10 minutes to warm up doesn't help.

I'm going to keep an eye on it, but guess I learned something new again today.

Thanks for the replies. Read 'rev limiter' before, just swore I'd had it above 3500 in park before.