What did the estimate say they where going to fix?
Is your Disco a I or a II?
It almost sounds like sticking valves, not closing all the way or lifters. (Disco I)
Have you done a compression check?

 

They said:
new coil pack
new cats....causing o2 sensors to go bad
new belt (drive)
new instrument cluster
head gasket leaking fluid into cylinder

The crack heads wanted over 10k to fix it all. With help of here and some on-line shops I was able to do most of this work my self for under 800 bucks (including welding the cats).

It is a 96 disco 1 4.0. I was hoping the sea foam would losten the valves, if they are sticking. I really dont want to have to open this thing up if I dont have to.

No compression check yet.

I did check the spark on a whim today. I plugged the timing light to all the even number wires. I found the #2 to be firing slowely and #8 to be normal.

#2 was; click........click, click, click.........click,click..........click, click
#4 was a little faster, kind of click, click...click...click, click..
#8 was click,click,click,click,click

This only occured while the engine was in its funk. Otherwise they all fired fast. What does the coil plug into? Perhaps that is the culprit. I still havent ran the fuel down yet to try that.

 

I also found the computer to be loose. The cover came right off and the computer wasn't even bolted in! Would a bad computer cause this problem?

 

If the ECU is messed up that could do it, After all it does control everything.

 

I have been looking all over for a new ecu (I can only imagine the cost....) is the stealership the only place these can be had from?

 

Have you tried www.roverlandparts.com?
Before you buy a new one try some of the otherthings first, like your grounds, check the circuit board on the ECU for cracks.

 

How much coolant is the motor using?
Do you have coolant on the spark plugs fouling them?
How did they check for cracked heads with out pulling them, it may just need head gaskets.

Get the ECU put back in place and see if it helps.
You can get any ECU from a GEMS motor BUT you will have to have it coded to work in your Disco, the Dealer or someone that has the interface and software to do it, a Rover shop.

Do you have a Rover shop that can give a second opinion?

At this point a crank sensor is $40 from AB it couldn't hurt sometimes they don't go out all at once.

Does the exhaust have a odd smell? Coolant will do that.

I have never heard of 13 , 14. & 16 codes what OBD II reader do you have?

 

Sorry, I abreviated the codes. P-1313, P-1314 and P1316. All point to emissions/ignition related.

Coolant is actually fine, I think they were making a guess. I had sea foam in the crank case and it looked like water bubbles. I have sence replaced all that oil and it looke fine.

The heads werent cracked, the head gaskets were (acording to them)

I found the sensor. 60 bucks seems fair to get this things working right, I just want to make sure this is the part I need before sinking more money on useless parts.

 

On the codes I just wanted to make sure no one was blowing smoke.

So lets look at what they said,
Coil pack
Cat's,,,02 sensors
Drive belt
New instrument cluster
Head gaskets leaking.

It looks like that you have done everything that was on the list.
If the cat's are pluged up it would not run good sometimes.
The only thing left is the coil pack but thats about $550 (new)so that was why I thought a crank sensor would be the next step.

When you go to a dealership they will wright a estimate for everything you need not just what you want to fix the problem you have at the time.

 

It looks like Rover Land Parts has used coil packs for $275 and new ones for $400.