COgirl470

I just bought my 2007 GX470 last Friday. Last night I drove it home in the season's first snowstorm. I've got plenty of experience with winter driving and Toyotas, so I thought I knew what to expect.

I dropped down to 3rd gear for a long hill and the transmission or engine started surging. It would hold at 1100rpm, then suddenly jump to 1400rpm when my foot was not even on the gas. Then it would drop back to 1100 again.

I don't know that I'm willing to live with this. Does anyone know what could be causing it? I read some posts on other forums that talk about cleaning the MAF sensor, or using premium gas. The car has 78000 miles on it.

Thanks, everyone!

COgirl470

I may have an answer - a friend just asked if I had had the super defrost on, which I bet I did. I'll try it again tonight and be sure I have it off, and then report if it was the A/C condenser going on and off.

Wronglane

You meant the engine was surging,not the transmission,right? What is "super defrost"?

mrblister

Going down hill if you step on the brake the trans automatically downshifts to slow the
speed but the rpm goes up because your using the engine to brake the speed

UpStarr

super defrost ? Please explain

chiph9

That's classic engineering, that is.

Chip H.

COgirl470

LOL! Super defrost is what I call it when you hit the defrost button that diverts everything to the windshield and usually runs the A/C compressor (at least it does in my Sequoia).

I tried last night and this morning with all climate controls off, still surges. Tried turning off traction control, still surges. Did it in both 4th and 3rd. Engine holds at lower rpm, then all of a sudden, pops up about 500rpm and then back down. Makes it feel like you are freewheeling for a second. I'm getting a little used to it, but it doesn't seem like something that should be happening.

chiph9

I think you're going to need a trip to the dealer.

Chip H.

mann777

CO-Girl...you need to visit the Dealer, I probably think the fuel flow valve intermittent malfunction. but anyways get to the dealer and see if any codes are probably locked into your ecm.