Lunge when Stopped

I have seen some digressions on a couple of other threads about the truck lunging when stopped.

I too have noticed this in my truck, and I wanted to start a whole new thread dedicated to that.

I'd just like to know if anybody else has seen this, does it go away eventually, and if you've talked to Toyota, what was their response?

Thanks.

 

Can you describe the symptoms?

Coming to a complete stop? Gentel pedal pressure or hard?

While standing stopped? Does it pulsate?

More info please.

 

This only happens when I'm already stopped (as in at a red light, etc.), and I have the brake applied fully to remain stopped.

All of a sudden, there is a lunge which actually feels like someone bumped into your rear bumper at a very low speed. 90% of the time, I'll actually look back to make sure this didn't happen.

I've heard on here that some people feel this only when the AC compressor is on, but I've not done any real testing to see if it is limited to when it's on in my truck.

 

I have noticed a slight idel increase when the AC kicks in or the evap thingy
opens to vent off the gas tank fumes. My GTi used to do this.
But, RPMs never jumped up so much to make the car or truck want to lunge.

 

Not to worry. It'll go away. It happened to mine when new. It happens intermittently and the cause is the prop shaft not returning into place smoothly upon breaking. It does so a little late and makes the truck lunge. The only remedy is to lube the shaft which Toyota did and the problem went away. Talk to the chief mechanic at the dealership.

 

I have the lunge too but i never noticed it till i read about it on this site and started looking for it. It doesnt bother me enough to do anything about it.

Themaster: are there any negative long term affects if you dont get this taken care of?

 

I don't know if you had caught this: http://www.wsmv.com/iteam/14304072/detail.html

 

I have an 07 Access Cab. On a downhill or flat surface I do not see this much....But if I stop on an incline (so I am not really pushing on the brake that hard) and the AC is on....bingo, when the compressor cycles I feel a slight lurch. It is just like someone very very slightly bumping into you. My truck actually only moves a few inches at best cause the pads do take a better bite, but it is spooky till you know what is really going on

Just my $0.02

T

 

That sounds like a plausible explanation...and yes, it is extremely spooky at first...

 

Not really. Wear and tare will eventually resolve it. Lube will solve it sooner.

 

I agree with your explaination. The only other thing I can imagine it being is the trany finally kicking into low gear. What I don't understand is why this happens at all. I have had several new vehicles and none of them have done this. My '08 does this too so I'm going to try to make sure I drive around without the AC on and see if it still does it.

 

The truck is downshifting back into 1st gear.....you'll feel that rpm increase as it downshifts. Our Grand Cherokee we owned did that also.

It'll feel worse with A/C on because the engine will run a higher rpm with A/C running.

 

My truck has done this since day 1. When stopped at stop light with a/c on or defroster on the truck will lunge forward if you don't have the brake pedal pressed firmly...pain in the ass and unsafe.

 

I have a new 08' and it does this as well .

 

Yes, reconfirmed today. My issue has nothing to do with the transmisson nor any drive play, shaft "wind-up", or anything that needs to be lubricated.

I just push slightly harder on the ole brake pedal and viola.....no more slight lurch when the compressor kicks in. Without the compressor operating it never does it.

I Fully believe it is just a case of re-calibrating me.....ha

At any rate, if this happens without the compressor cycling...then one of the other issues mentioned may be causing it.

T

 

I have the same symptom - lunging when at a complete stop. My personal assessment is lazy brake pressure. I'm seeing a special trainer at the gym in order to compensate.

 

I've experienced that lurch too, but haven't diagnosed it. I usually have the radio too loud to hear the compressor. It's starting to bug me. I hope it is as simple as getting used to applying more brake pressure at red lights.

 

haha! I like that! Someone finally owns up and blames themselves instead of the truck or the manufacturer