Hey guys Ive had my 2000 Disco 2 for almost 2 years and after some catching up on maintenance she has done well and I appreciate all the info on here. Over the last few weeks she has began to drop revs in 3rd gear. Going about 45 mph it will drop from just under 2000 RPM to a little over 1000. At first I thought it was just dropping into fourth but after paying close attention realized it was stumbling. It would only do it on a hard up hill pull at first but now it is almost every time it runs through third. I have yet to get a CEL but It feels like its getting a dead miss and just stumbling but only for a second, about as long as a gear change. I can manually hold it in 3rd and it goes nuts in that RPM range with what sounded like spark knock. Hard to tell with mud tires at 45. Plugs and wires were done about 9000 miles ago but they were part store specials so maybe? Plugs are NGK but I cant remember which kind. Any help would be appreciated!

 

Lots of people will tell you that you need a scanner (Scangauge, UltraGauge, etc.) to determine which cylinders are mis-firing. Even with no CEL, there may be pending codes to point you in the right direction. Good luck, and keep us posted.

 

I scanned her today and turned up no codes but I used a cheapo scanner. Guess I will have to keep it in the sweet spot until something turns up. I hoped somebody had experienced something similar before.

 

I had a similar issue last year that i battled for almost a month. No fault codes or warning lights and went at it like i had a tranny shudder. When I got nowhere with that i began pulling spark plugs and wires one day, low and behold a boot seperated from the lead. You know the rest.

 

X1 .... Chubbs is correct. Most ignition faults tend to only show under load. It's worth checking your ignition leads and whole system for an HT leak to earth which is a common fault on many vehicles.

 

Not sure, but when the transmission shifts it sends a signal to the ECU to reduce torque. Because it's cable and not fly-by-wire, it probably does so with a lean bump on the injectors and a momentary reduction in spark advance. If under load, it would be a fairly severe reduction. The lean-out and spark retardation could cause a plug fault that it doesn't recover from right away, especially so if a coil is weak or plug is clapping out.

 

Honestly, my last two discos have always had that happen in third gear, I know exactly what you're referring to. I'm at 150k on my current disco and it's always done it.

 

What? A stumble or cut-out after 3rd gear shift when accelerating?

 

I don't know if you'd call it either of those, I've always noticed a slight 'flinch' in third gear. Like I said though, both my 04's have always done it.

 

Mine has always had a slight stumble when I hammer the throttle and downshift to pass a car....no idea why. Neither does anyone else. I can make it do it in four low also (that's when I've had issues with it), like when climbing a steep hill slowly and it downshifts to a lower gear, the rig will fall on its face for second and almost bring it to a stop (it doesn't always do it though)....I feather the throttle and picks right back up. Thinking back about my last high desert trip, I was about ready to try and figure it out after I got back home, but honestly I forgot about till just now reading this thread!