I posted this in the General tech forum, but thought that here was more appropriate...
I have a 2003 Disco with 157k. It will start and idle, but if I give it any gas it acts like it is starving for fuel. I can rev it up normally if I give it starting fluid. It acted similarly when the MAF went out, and needed to be replaced, but it ran great if I unplugged the MAF(was replaced about 4 years ago). Now if I unplug the MAF, it just dies, and is difficult to get to restart. I thought fuel pump, so I replaced it. No improvement whatsoever. I thought fuel pump relay, so it pulled it, and tested it, it clicks, and was getting 11.8v through it with my multimeter when closed with a battery measuring 12.7v. Relay should be functioning I think? The CPS was replaced by a dealership about a year ago when my Mom was borrowing it for the summer. Also all four o2 sensors (OEM Bosch is what I bought) were replaced last year, and I probably haven't driven it 300 miles since then.

Codes in order:
P1884
P0102 (figured it threw that when I unplugged the MAF while it was running)
P0300
P0301
P0308
P0303
P0302
P0175
P0172
P1230
P0463
P0304
P0306

 

It doesn't look like it's starving for fuel. At least not all the time. The P0172 & P0175 are system too rich codes.
At the same time, the P1230 is defined as a "low speed fuel pump fault condition".
What I would do is, make sure the fuel pump is getting full power and ground. One way to do this, with the least amount of work, would be to take an amperage reading right at the relay. Remove the relay and connect a multi meter in series on the load side connectors. The fuel pump should draw somewhere around five to ten amps, roughly. If you get a reading below four or five amps, then you should check the power and ground at the pump.
I've seen voltage drops on both power and ground. It's more common to see problems with the ground on fuel pumps. Because they are usually connected to the frame somewhere near the back of the truck where they can get salt and water on them.

 

I thought the system too rich codes may have been lingering from the o2 sensor codes before I changed them out. Is that not possible?

 

I also thought the system too rich could have been from spraying the starting fluid in it to see if it would run well if I introduced fuel manually.

 

So I pulled the relay, and checked for amperage, and I got 5.9A.

 

Okay, that sounds alright. Could you hear the pump run when doing the amp test? I'm just wondering if it sounded normal or if it sounded like it was running slow, or labored. Does it sound the same as when it primes, when you first turn the key to the on position? If it sounds like it's running slower with the relay powering it, the relay may be bad.

 

That's possible, those codes can take quite a while to clear up on their own. Sometimes you have to reset them because the computer will ignore the sensor and use a substituted value until they're cleared.

 

This is not likely because the rich condition would have to occur in two consecutive drive cycles to generate the codes.
Do you have a scan tool with live data? If so, you can look at your fuel trims and they will tell you more about what it's doing. Whether it's adding or cutting fuel.

 

I had to pull the relay out to check for amperage. How do I check it with it in? Also, previously I checked for voltage at the pump, and got 12. I just checked, and I had .4v... But I don't think it would be able to idle with that little of voltage. Where is the ground for the fuel pump generally located? Although, I can charge the pump with a 12v battery directly, and it still doesn't improve.

 

I had to convince the parts store to let me take the scanner home, and bring it back real quick, since I can't get the rover to them. I don't have one yet.