Rev hunting during driving

[D4MJT]

Hi,

I've noticed over the past few days, when I'm coasting in 30mph limit areas, regardless of whether my O/D is on or off, my rev's hunt quickly between 1,500 and 2,000rpm, like the rev needle is bouncing between the two? What would cause this? I'll try and get a video of it happening to show you guys.

:icon_bigg

 

[Mo87NA]

It could be a couple different things actually. I have seen some old Toyota tachs and speedometers begin to wear out and bounce. Do you have an GTE or GE?

Mo

 

[D4MJT]

It could be a couple different things actually. I have seen some old Toyota tachs and speedometers begin to wear out and bounce. Do you have an GTE or GE?

Mo

Hi,

sorry, I guess it would be handy if I put that information in my sig, it's a 7M-GTE, if it helps any, I've recently reset my ignition timing, could this have anything to do with it?

 

[martin p]

Its because you are right on the edge of it cut off from cruise to idle,
Mine does this too, as when you are coasting there is little to no load on the engine so it trys to return too idle, But the speed is Just enough to hold it up, Not explained very well, but that's my poor way with words LOL.

 

[Mr. Y]

My buddy had such problem... Fixed by TPS calibrating and checking according TSRM.

 

[subjug4tor]

Had the same issue here, fixed it by correctly adjusting the TPS. If the idle pin is making contact too far into the throttle depression, the plate will be open, but the engine computer will think that it is still closed (idle).

The ECU cuts fuel at a certain RPM (around 1600 I think) to help emissions when letting off the gas. The RPMs go up past 1600, but the ECU still sees idle, so it cuts fuel, then after the RPMs drop, fuel is returned, making them rise again, hence, the bounce back and forth.

 

[jetjock]

^ What he and Mr Y said. And next time you set ignition timing first check no codes are present....