Vehicle info - 1996 Discovery 1 SD 4.0L 5 Speed manual.

Firstly would like to say I have searched through all the threads I could find and honestly none of them really seemed to cover what has been happening with my Disco for well the last while. It all started after I had redone the oil pan, and valve cover gaskets(leaks on both) and put everything back together. It seemed to work fine for a few days, and with no leaks , but the working fine sadly did not last very long. After about 4 or 5 days after warming up and stopping at a stoplight/stop sign the idle would stay round 1.5k-2k, and would not kick down if I did not either give it a quick stab of gas, or pull up on the pedal. So I thought well cable is old and I do have a new one, I will do that on next not raining day. Fast forward about 2 weeks, gotta love Oregon winter :P, and I get the new cable put in after a lot of fight with getting it attached down at the pedal. This was mostly due to I have big dumb hands, and not tiny little ones that would be perfect in that space. Anyway so I get it in, and get it adjusted to how I had the previous cable, which was very little pedal travel before engaging, and it is still sticking. So I took and got some heavy duty water resistant silicone, and gave the springs, and any part I could a good spray, but it still was sticking.

After a bit of rain/snow, and research I found things about IACV and Throttle body issues, so I took and gave them both a good cleaning with B12 till I was satisfied that they were clean. Put everything back together and 0 change. I then took the cable off the throttle body side, and tested it there. Hold it round 2k, then let go and it went back to normal as it was supposed to. Hook the cable back up and figured well maybe I have it a little too taught, so I gave it some slack and it would go back down to normal idle as it normally should, but there was also about 1/2+ of dead pedal before it would engage, and if you just let the clutch out the car would move on it's own as if you were giving it a tiny bit of pedal(5mph or less probably). Proceeded to remove cable from TB again, let out clutch and it would move a bit, rather not wanting to and stall out. I did notice that when it is sticking I could push in on the part of the new cable that feeds into the firewall and it would return to normal idle.

So not quite sure what is going on here as it is a bran new cable. Granted it does look quite different from the cable that was on the car when I bought it, but that one is probably from when the car was still new. I have attached pictures of the routing which was the same as when I removed the old cable, and the differences in the cables. Thank you very much for reading, and sorry it was a bit lengthy just wanted to give as much information as possible. Also sorry for bad quality of pictures, no camera and cell phone died recently.

New Cable

This is the different setup than was on original, also the part that I pushed on and idle would go back to normal.

The way the cable was run previously as well as now.

Old cable

 

I was going to say clean your AIC valve and MAF sensor but it seems you’ve done that. How are your spark plugs looking?

 

Haven't given the MAF a cleaning yet, as I couldn't find my can of MAF cleaner. I know it's somewhere in the shop :P. The spark plugs should be good as they are less than probably 100 miles on them, but plan on checking them and giving the MAF a cleaning on next not raining day, or I should say when it stops raining so hard for about 20-30 min. I did notice a little odd thing today when I was messing around before rain started pouring down. I got the part of the cable that goes into the firewall so it's as straight as I can possibly get it, but still it doesn't return correctly unless there is a lot of dead pedal, but after that there is about 1/32" or less of normal throttle, and any past that is almost like it is floored. Another thing I plan on checking is the TPS as mine looks a bit far off from where the RAVE or other pictures I have found appear to have it set. Not sure if that will have anything to do with it, but eh can't hurt to check.

 

So update (2/12/2021) Went out and cleaned MAF, and the IACV(again) and adjusted the cable on both ends. From what the person at Atlantic British told me the part with the spring that goes through the firewall is used to adjust pedal tension, so for less dead pedal I guess. Anyway did all that and unfortunately still having the same issue of either a lot of nothing then sudden accelerator action, or barely any dead pedal but sticking after you let your foot off the pedal. I am starting to think perhaps I need to clean the intake cover again(this time pull it off), and or that it is possible the TPS is going and causing the butterfly to stick, but not sure on that theory. As if you disconnect the cable from linkage it doesn't stick at all. Which makes me go hrrm, and think well it did it with the old cable, does it with the new one. So either something else is going on, or the old cable was on it's way out, and the new one is possibly defective. Not really sure, but going to try toying round with it on the next not pouring day which here in So. Oregon could be tomorrow, or a week from now :P.

Thank you for reading and if you have any suggestions or tips please let me know, as I am rather out of my knowledge base at this point.

 

Springs on TB aren't broken are they? Throttle Body plate should have springs to make it snap back to the closed position. I have seen a few with broken springs.

 

The springs don't appear to be broken but will take a closer look next dry day. Odd thing is that if cable is not connected and I move the linkage by hand it always snaps back to normal. Though with old and new cable it sticks. Also should add I looked into it more and apparently the TPS is not an adjustable part, but did see where when it starts to go it can cause high idle sticking. Hopefully its not the TPS though as those are far from cheap 😥
*edited to correct auto correct sillyness from cell*

 

Update 2/15/2021

Well I went up and double checked the springs and they both appeared to be fine, also did a test with the old cable. The test was have it connected to linkage, and pull on the end that would connect to the pedal to see if it was returning to normal, and of the 6 pulls I did every time returned to normal. Not really sure if that says anything, but am going to try Wed. to do the same with the new cable, and try to do a more direct routing if possible. Possibly try not underneath the brake booster since that was how the old one was run since we got it, and how I ran the new one since the clip/etc isn't there where the Rave says it should be. Also on a theory from my brother gave the pedal return spring a good shot of silicone, but sadly this didn't change anything. I did however go over to my mom's 95 3.9L and gave it's pedal a test and that thing has a really firm pedal, didn't appear to be really any dead travel to it, and the pedal travel in mine is fairly lose. Not sure if any of this helps, but figured should throw it in just in case.

*Edited to add information*

 

that is a lot of strange wiring in that engine bay

 

I just see the 1 non OEM red wire running along the bulkhead which isn't stock. The Coil Pack plug is no longer clipped into it's mount tab, and the yellow wire loom = SRS.

 

Oh there is a lot of non stock mickey mouse wiring that I have had to and am still replacing in the thing. Someone thought they knew what they were doing, and hooked a power wire(not sure if constant) from stereo into the rear passenger window fuse and well that is a satellite I get to replace as it melted the spot and part of the wire. Doh, keep forgetting to put the coil pack plug back on correctly, but then again I do have a bad memory :P.

Anyway update for today - Went out after doing some looking online at the linkage and such and thought to double check and it was a good thing I did. Both on what I could find online, and my mom's 95 3.9L there is a spring on the linkage that is not on mine. Not sure if that is the problem as most parts diagrams list it as a spring or some a return spring, but I noticed on the 3.9L it just connects to two points on the linkage. Figured maybe someone might recognize it and let me know if maybe it could be it. Also did notice that the first spring(PN ERC3792L)is a bit less straight than the one on the 95 3.9L, but not sure that would cause a issue. Anyway hope you all have a wonderful day, and will keep this updated as I am able.
*Edited to add image*