Put on a set of headers last week and the 97 disco has been idling at 1500rpm constantly. It pops down to 1000 in drive the cats are not even 11 inches down from where they where orig. Everything is hooked up as it should be. I checked numerous times. No Idiot lights just annoying high idle.

It must need injectors!

Or Midol

this is easy. your battery is dead and the injector pulse is lengthened allowing too much fuel to the engine, thus the high idle. probably only in some of the cylinders though due to the difference in resistance in 12 inches of 16 or 18 gauge automotive wire.

Reset adaptive values? I wonder if the EMS was able to recognize something changed.

If you can't find a way to reset the adaptive values, a coupla drive cycles might resolve it.
Otherwise, TPS issues can cause high idle on GEMS engines without illuminating the CEL. REading the codes would be a real help here!

As Crazy as it sounds its the cruise control! For whatever reason the cruise control is pulling back the throttle. PT I think you where darn frikin close because I adjusted the throttle hand to come back farther than stock and it stayed at about 900 for 15 seconds stumbled like crazy and kicked the throttle back. Unhooked the cruise cable and all is well! Thanks for the Help. I see spork is keepin it alive!

Thanks spdork

I live for the grief. I was convinced the guy left off the battery cable at the engine when he changed his starter and it was getting ground through the shift cable. I have seen it a few times. It would not have been the solution to all his problems. But would have heigthened them. I wanted to help people learn how to recognize the signs of voltage drop. And the importance of stoping and retracing their steps sometimes. But it turned into a feeding frenzy that I would suggest something so out of the ordinary. I did get to learn some things about people I thought I knew though. Should benefit me in the future.

Not about you though spdork. You pretty much acted like you always do. And good synopsis of my plan of attack.

Thanks spdork

I live for the grief. I was convinced the guy left off the battery cable at the engine when he changed his starter and it was getting ground through the shift cable. I have seen it a few times. It would not have been the solution to all his problems. But would have heigthened them. I wanted to help people learn how to recognize the signs of voltage drop. And the importance of stoping and retracing their steps sometimes. But it turned into a feeding frenzy that I would suggest something so out of the ordinary. I did get to learn some things about people I thought I knew though. Should benefit me in the future.

Not about you though spdork. You pretty much acted like you always do. And good synopsis of my plan of attack.

just giving you a hard time. i did learn something new from all your posts. although suggesting something that unlikely is a stretch and voltage drop in 1-2 feet of wire is not going to make a difference in this case unless the wire was damaged in some way. and like PT said, if the voltage was that low, the SRS light would have likely been on like it is in my rover. most guys here give me as hard of a time as i give them, so i don't feel to bad about it.

Actually if that cable is left off it does not set the SRS. And it does funny things with the ignition on distributor cars and fuel injection. My experience anyway. Pink Force and all.
Think about it. The ground on a LR Disco is a strange arrangement. From battery to inner fender to frame. Follow frame, frame to engine. To many connections to its main users, the starter and alternator. And rather light gauge wire IMO.
I often rewire it. Heavy gauge cable from battery to engine block. regular gauge cable from same connection to frame. Leave connection from frame to inner fender, cut the cable portion that use to run from the battery to the inner fender and leave the rest. And try to make a ground from the engine to the bulkhead.

I also think the factory arrangement is hard on alternators.

i rewired my grounds when i put in my wrangler power alternator. the stock setup is definitely strange to say the least. i wonder what the reason was for that arrangement from the factory.

My Disco also has a big-ass braid on the left side from frame to engine. Seems as though it is much more robust than the wimpy ground from the battery to the fenderwell and onto the frame. Seems as though they often corrode badly where the fenderwell mount is-no doubt from proximity to the battery.