Just got a 2002 Discovery with 108k on it. Driving through loose sand in low range about 5-9mph, tried to stop by applying brakes. Engine RPM stayed at 2500 and full brake pressure did not stop the vehicle. Shifted from Drive to Neutral and stopped. RPM remained at 2500 and when I shifted back to Drive with brakes still applied, it started forward again. So I immediately shifted back to neutral and briefly revved the engine to 4000 RPM. When I let off the gas, the engine returned to 1100 and the braking problem ceased. I hadn't had any problems with the brakes before then, and I haven't been able to duplicate the problem. Any ideas?

 

Why are we doing all the work? What have you checked so far, after all, there are only 2 things that will cause this, a bad/dirty cable or a dirty t/body. Go check them and get back to us.

 

What kind of work is there in speaking from experience? I can read all day about torque converters, EAT ECU's and brake pedal switches, but I'm asking if anyone's seen this before and knows how to diagnose it before I go chasing my tail.

I saw a thread that was similar, about cruise control not disengaging, but this was not a cruise control issue since I never engaged it. On 44-18 of the D2 Workshop Manual, it talks about the EAT ECU monitoring kickdown. Maybe a problem with that component could cause what I saw. It could be a sticky throttle, a corroded cable, a bad torque converter...

There's a wealth of knowledge and experience on this forum. Tell me what you've seen.

 

IMHO monitoring kickdown won't make engine rev to 4000. And electrical parts like TPS can't make the butterfly valve open enough to allow the kind of air required for 4000 rpm. So linkage seems a logical place to start. Could also be inside the throttle body with enough gunk buildup to stick the butterfly valve.

 

Where are you located?

 

The engine was maintaining 2500 so I pressed the gas in neutral and revved to 4000 to see if I could unstick anything (linkages, valves, etc...) and then the engine returned to about 1100 or so.

So I think you're right about it being the butterfly or a linkage issue. I just wanted to make sure there wasn't some funny electronic issue that could cause this. I'm new to Rovers, so I figured I'd ask.

I've got some air intake cleaner to spray into the throttle body. We'll see if that works. Thanks for the help, Savannah.

 

Just moved back to Corpus Christi, Texas from Whidbey Island, Washington. This heat's gonna kill me.

 

It ain't hot just yet....

 

Lube the linkage and pull off spring with silicone spray.

 

Thanks for the help. I've lubed it up and sprayed it down (linkages, spring and t-body). Unfortunately since I can't duplicate the problem, I won't know if I've fixed it until it happens again...