another interesting problem

[widepud]

96 discovery 171,000mi. while driving at a regular open road pace the engine seems to kinda crap out and loose about all power. it never dies nor does a check engine light come on. the only way i can discribe it is the exost makes a sound kinda like a low speed downshift it just kinda makes a low rumble. and it was doing it every once in a while and i would just let off the gas for a second and it would clear up i tried dry gas but that didnt help and it did it worse than usual this morning on the way to work. also i just changed the plugs and wires a few days ago but it also did this before i changed them. any ideas?

 

[joey]

Tell me do you notice the speedometer jumping or going to zero when this happens?

a quick test, when in drive and this happens, drop it down to 3rd and see if it goes away.

 

[widepud]

i havent noticed the speedometer do that ill try what you suggested at the end of the day when i go home.

 

[Brownie92]

Could it be a bad cat covertor? I had a jeep that the cat guts broke loose and would intermittently plug the exhaust. The result was no power and horrible mileage. Although if that was the case I would expect a check engine light. On a cool cat just slide under the truck and smak the convertor and listen for loose parts. Just something to think about.

 

[widepud]

i spoke w my uncle who also happens to be my mechanic,and i actualy took him for a ride in the rove while it was having this problem and he suggested it was a bad cat. ill know soon since i ordered a new cat. since the pipe broke just above the cat and it needs to be replaced anyway. so i got a factory fit replacement that has both cats and the y pipe. i ordered it today,also have 2 o2 sensors coming as well to replace the fronts . also to answer joey i did try what you suggested and no luck it also does the same thing when you shift to 3rd.

 

[joey]

Then it is a good chance it is the CATS.... Remember if the cats go bad, something caused them to go bad... either direct hit from off roading or from a bad part upstream... i.e. O2 sensors.. fuel temp sensor, injectors putting too much fuel down stream for what ever reason.

 

[widepud]

well im really hoping that the stuff ive ordered clears up the problem since it was kinda pricey and i cant wait for it to be in good running condition.it by far the coolest truck ive ever owned so hopefully all works out well and if not you'll be hearing more questions as to what else could be the cause. thanks for all the help and ill keep you guys updated.

 

[widepud]

new cats and o2 sensors didnt fix this problem

 

[joey]

I would start with the fuel system then... bad injectors (or just dirty), fuel filter, fuel pump, With a 171k it could be either or all three.

 

[widepud]

ill take a look at those.