[fpdavis3]

OK, I got a new one on my Discovery. When I step on the gas while the car is in reverse, the engine revs up even when you take your foot of the accelerator pedal. The first time it happened I was climbing up some stairs at Little Moab. It was a little un-nerving being pushed backwards down some rock stairs with a drop off on one side but back to the story. Now, ever since then any time you accelerate in reverse the engine want to keep revving. Once you stop and place the car in neutral, it revs to about 2000-2200 rpm and won't go down until you give the pedal a good stomp, then it will return to normal. When you back up without pushing the pedal it stays in idle. In drive the car acts normal with the exception of on cold starts the idle would sometime "pulsate". I have changed the IACV valve and cleaned the airflow sensor and the cold idle problem seems to have gone away. But the reverse problem is still there. Any Ideas?? The Disco is an 03.

 

[Bosnian Discovery]

The throttle of the Disco is (thankfully) linked mechanically between the gas pedal and the throttle body. There is no "drive-by-wire" system that could be at fault.

What likely happened is that your throttle cable is kinked or misrouted somewhere - and it's getting stuck. It could even be a dirty throttle body that's too gummed up to close.

It's weird that it only happens in Reverse, but I don't think reverse is causing it.

 

[fpdavis3]

Thanks for the reply. I do appreciate all help. The way the car acts, it has to be something with reverse. The car has been like this for over a week. It is not a random act, it happens every time you press the pedal in reverse and not once has happened pressing the pedal in drive (or any forward gear). The car has been driven every day with the same results. By the way, Codes P0101 and P0505 were read at one point during this. No codes have been thrown since changing the IACV and cleaning the MAF sensor.

 

[Disco Mike]

Cleaning the MAF may have killed it and that may be your problem.

 

[fpdavis3]

I drove it for about a week before cleaning the MAF. It was the same, before and after. Not saying the MAF is not bad, just saying if it is bad, it was bad before I cleaned it. Yes/No??

 

[fpdavis3]

Ok, I think I have it fixed. You guys that pushed for a mechanical problem were correct. After you guys suggested mechanical, I took a hard look at the throttle cable. I noticed the cruise control cable seemed to be pretty tight. I referred to rave manual and adjusted both cables (throttle and cruise) to the spec referred to in the manual. I believe I had a couple issues at once. I was also swapping out my IACV and have decided one of them is bad. After I got the cables adjusted and the "good" IACV in, the idle has been very good and stable. The vehicle is still pretty new to me and I realize it has been idling a little high the whole time I have had it. I have owned a 95 for many years and should have put 2 and 2 together but, I drive the 95 and my son drives the 03 so I did not catch on to the high idle. Thanks for all the help from everyone!! Sure nice to have access to lots of knowledge!!