| Author | Message | ||
     MHawkins (Mhawkins) New Member Username: Mhawkins Post Number: 2 Registered: 07-2003 |
I started having a bit of trouble with my 96 Disco about 4 months ago on a long road trip. At highway speeds 65-75 there were intermittent times when it would feel like it was losing power for a few seconds at a time. This has continued every so often but only at highway speeds. Then about 3 weeks ago the check engine light came on while on the highway so I went to autozone to pull the codes and they indicated cylinder misfire #5, random cylinder misfire and excessive emissions misfire. I had them clear the codes and they have not returned and the truck was running fine. Now when you reach speeds of 55-65 the truck starts to shake, although still shifts ok, and you can either exceed these speeds or slow down and the shaking goes away. Runs fine just driving through town. I dont have a lot of experience with diagnosing these kind of problems and was hoping for some help. I have read about possibly sticky valves or a speed sensor issue. Thanks for your help. | ||
| eric johnson (Eric2) Member Username: Eric2 Post Number: 52 Registered: 05-2003 |
Well, first of all, is it a suspension shimmy/shake or an engine vibration problem? Reading thru your post seems to describe two problems. Secondly, I thought Autozone is a parts store. When did they become a LR repair shop? So you got some problems...what did you do to correct them? Misfires and excessive emissions. Maybe O2 sensors, but that is an uneducated guess. | ||
| Leo (Leo_hallak) Member Username: Leo_hallak Post Number: 102 Registered: 02-2003 |
Make sure the basics are covered like.. plugs, wires, fuel and air filters. From what I have read the sticky valves or vehicle speed sensor can cause this.. I was having the same problem, I would be at like 65/70mph and I would let off the gas and then step back on it and I would get horrible power loss and shake. At that point I had new wires, and plugs and air filter.. so I changed the fuel filter and put in a bottle of techron fuel system cleaner. and took the advice to drive the car like you stole it.. http://www.chevron.com/prodserv/nafl/auto/content/fueladd.shtm From that point on I havent had the problem. Either one of those doesnt cost much to try. -Leo only posting from personal experience. | ||
| Jack Edwards (Olered) Senior Member Username: Olered Post Number: 380 Registered: 04-2002 |
Easy Eric. He took it to Autozone to be diagnosed using the OBD reader. That was a good start. It means that he doesn't have a reader. I see nothing about suspension issues. This reads like a classic case of sticky valves. My truck 99D1 displayed the same issues. It started after a long trip. Then at highway speeds, it would lose power and vibrate. It felt/sounded like rolling your tongue/rolling an "R". RRRRRRRRRRRRRRR. LR replaced the VSS under warranty 3 times before I pressed them on the valve issue. It was the valves. | ||
| Joseph Bilyk (Denverrover) Member Username: Denverrover Post Number: 82 Registered: 02-2003 |
Sounds like unbalanced tires to me. JB | ||
| micky dee (Kincangokicker) New Member Username: Kincangokicker Post Number: 35 Registered: 06-2003 |
bent rim, or defective tyres. look for defects on the tyre it self. i had the same problem on the range rover. and it was the rims cause the tyres where bran new. | ||
| Jack Edwards (Olered) Senior Member Username: Olered Post Number: 381 Registered: 04-2002 |
So, bad tires cause fault codes?  Just kidding! I know, don't overlook the simple. I would think that he does not experience the shakes in town because he is not getting up to the required speeds for the shakes. It's hard to get up to 55-65 in the middle of most towns. I would have the tires checked, load balanced and such. This may correct the problems. | ||
| MHawkins (Mhawkins) New Member Username: Mhawkins Post Number: 3 Registered: 07-2003 |
Thanks for all of the great posts. I think I will start with the plugs, wires, fuel and air filter. I just took it out on the highway again to get a feel for the problem. It acts just as Leo described in his post, accelerate to about 65 and then let off the gas and then start to accelerate again and it starts to rumble like an engine rumble until you hit 70 and it goes away. Is this something common for a Disco with only 66000 miles. I would probably head to the LR Dealership but the closest one is 3 hours away and I'd rather learn myself for future use. I did buy the tires brand new locally so I will have those checked out. Anyone had to have a valve job done and what is it like to change the speed sensor(s)? Thanks again. | ||
| Jose A Cabrera (Jcabrera) Member Username: Jcabrera Post Number: 123 Registered: 02-2002 |
MHawkins, I too have a 96 that had the same problem (lost of power). It turned out to be the dirty valves. Good Luck! | ||
| MHawkins (Mhawkins) New Member Username: Mhawkins Post Number: 4 Registered: 07-2003 |
Jose, what was your solution? Thanks. | ||
| Jack Edwards (Olered) Senior Member Username: Olered Post Number: 383 Registered: 04-2002 |
I had a valve job at 49k! How lucky was that? There's a good write-up around here on changing the VSS. I don't think it's that hard. | ||
| Andrew Maier (Newman) Member Username: Newman Post Number: 75 Registered: 04-2003 |
I still think this is two issues...the potential valve issue that has been discussed, and another possibility you might check into. I had the same shaking at that speed and it was the panhard rod. | ||
| charles pastrano (Charles) Senior Member Username: Charles Post Number: 271 Registered: 08-2002 |
It is your VSS. Call Nathan at Discount Rovers. | ||
| Lucas Fernandez (Laferna) New Member Username: Laferna Post Number: 6 Registered: 07-2003 |
MHawkins; I am sorry to tell you, but you have sticky valves. I did not want to believe it in my case because I did not get a bad compression test. Your symptoms are classic valve sticking. My 96 did it at 56,000 miles. I saw the heads being repaired. There was lots of black carbon build up on the valves and the mechanic allowed me to feel how the sticky valves felt before he rimmed the valve guides with the updated bit that gets a looser clearance and later a cleaned valve in place. There was a significant difference. New teflon valve stem seals were also installed to prevent oil sipage into the combustions chamber. The 96 and later V8 for the US market used tighter valve guide clearance to comply with EPA tighter emissions. The tigher tollerances bind the valves as soon as there is any cabon buildup in the valve stems. My Disco runs fine now. Don't spend your monney in wires, coils etc. Get a good dignosis firts, but it is exactly what my Disco symptoms were. Forget the tire theories. Tires shake don't affect your engine power. Best of luck; Lucas. | ||
| Richard Dekkard (Richard_dekkard) Member Username: Richard_dekkard Post Number: 98 Registered: 04-2003 |
Mhawkins, While the advice here is all good advice, you are clearly stating two problems, and I think that confused a few people. The intermittant loss of power at highway speed only is most likely the speed sensor, which was mentioned above. The vibration issue at certain speeds that you can control and repeat are more complicated cause it could be more then one thing. Here are some of them. - worn bushings in panhard rod or radius arms. - worn out shocks - tire balancing - alignment - steering damper worn out Hope this helps... I dont think your problem is from stuck valves, as that will signaled more by a constant loss of power at any speed, loss of power when its very hot out, and rough idle. A vacumn test should spot it and takes about 15 seconds, but the vacumn test wont spot them all... It could still be your valves, but I doubt it, and that should be a last resort. Your symptoms just dont warrant it. | ||
| Bruce Potier (Brucep) New Member Username: Brucep Post Number: 13 Registered: 06-2003 |
vibration that goes away above a specific speed sounds odd to me, if you think that vibration is not engine related. Scoot under and take a very close look at those u-joints as well while inspecting items noted in Richards's list. |
