I've had problems in the past with my Disco, but with time off from work I was able to tackle alot of things I wanted to do. I changed my fuel pump, fuel filter, plugs and wires, replaced the tps, iacv, injectors. it has a little over 125k on the clock. I replaced all the parts above because, I was getting a popping through my intake. It started up fine after all parts were replaced so I thought everything was corrected, but when I put it in drive it did the same thing Popping through intake! I hooked up the fuel pressure guage with the key on the pressure is 30psi when I start the car its 37psi and it declines to 24-26psi in appx 6 seconds which I know is not good. any help is good help thanks!!
Sorry for the long winded post

 

Ya... Thats a bit low. Replace the filter and try it. Filter "Should" be visible through the Right Rear Wheel opening. This is assuming you have a 96, or Series 1 Discovery. If the pump is whining, it might be time to replace it as well. Although there could be several things that could cause this problem.

 

I just replaced my filter and pump along with everything in my previous post, so what could be causing the sudden drop in my fuel pressure if everything was replaced?

 

Yes, the pressure is a tough low, but I doubt that is your popping issue.
Usually popping thru the manifold is a burned or stuck exhaust valve.
Time to do a compression test and possibly a leak down depending on your compression.

 

thanks for chiming in Mike!!! I will do a compression test and post My #'s tomorrow I was also wondering should/can I do the ATF flush before the compression test or does it even matter. Also what is a leakdown test?

 

http://www.carbibles.com/engineoil_bible.html

Read though the Sludge part of this.

I doubt you have a burnt valve at 125k, probably a sticky valve.
Burnt valves were more prone on pre-96 models as they switched to hardened valves with carbon cutters in '96.

If you do a engine flush do NOT use ATF and be prepared to drop your oil pan.
Look inside your oil filler neck and see how bad the sludge is.
You may need to remove your valve covers and scrap the sludge off and then do a engine flush using a over the counter type of flush, like Gunk for example.
Then use diesel oil for 500 miles, change it and repeat.
Then switch to full synthetic after that.

 

I already took the valve cover off there was quite a bit of gunk in there. I found "black gold" when I was replacing my hoses mainly on the pass. side valve cover. what appeared to be a plastic "L" configuration was broken off into the valve cover. A couple taps with a hammer and old pushrod I got it out. so how do you safely remove the majority of the sludge on the heads? I've never had sludge like this on any of my vehicles before! please help one other question: what do I do about the declining fuel pressure?