Problems outta nowhere 04 Disco 2 4.6l

My coolant reservoir had a crack in it and my serp belt was looking bad, so I replaced both and also the small 1/4 inch hose from reservoir. Went to crank and was sputtering, then outta nowhere shut off. Serp belt is right. Fanned the gas and got it cleared up so went around the block. It died on me. I fanned the gas and stopped and started it back home. M and S are flashing while hill decent assist stays on plus check engine is always on since o2 sensors were unplugged. I got the codes cleared and the M S LIGHTS are staying off but can't get it to crank and run right at all without fanning gas just to keep it running...

And why did you disconnect the O2 Sensors? They could be the source of your problems.

No they have been unplugged for well over 2 years. The exhaust is straight pipe no converters and one muffler. Had new coil packs put on in April, with new plugs and plug wires. I've checked most wires around the areas I worked on and no grounding or shorts. All fuses are fine and I have a new mass air flow sensor which I double checked and is properly installed. It seems as tho it's choking when I give it gas, Boggs down, then shuts off, but eventually it will roughly idle. But yesterday I couldn't get it to fire up. Starter works and engine turns over, oils clean. Has 120,000 miles on it.

I worked on it again today, wouldn't crank but had raw gas smell, ran OBD and got P0123. Throttle/Pedal Position Sensor/Switch "A" Circuit High Input, multiple misfires -3,4,6,& 8.

With the O2 sensors disconnected, how does the computer figure out how much fuel the injectors should be adding? I can't remember right now how it affects the fuel mixture, but it will either go full lean or full rich, either of which isn't good. I've heard of folks adding a resistor to the mass airflow sensor to fool the computer into thinking the O2 sensors were in place. Odd situation.

'99 Disco II
'95 R.R.C. Lwb (Gone...)
'76 Series III Hybrid 109
'70 Rover 3500S

I'll check that out, I'm thinking now that there was damage done from the coolant tank cracking and spraying hot coolant everywhere. I'm slowly tracking back from that area. Actually when when changed the exhaust over our gas mileage was much much better. Didn't see any loss of power and I travel 18 hours every year up the coast with maybe three gas stops. Maybe it is confused but I didn't change anything but the coolant tank, a few hoses, and serp belt then this started happening. When I got down the road. Weird.

Now that I've looked back over this post, I've decided to think about what happened first, 'Coolant leak from cracked reservoir.' The last time I had a cracked overflow tank it was because the head gasket had blown and over pressurized the system. And.. the resultant blast of coolant can't be good for electrics. Also, the great mileage might be down to the injectors running lean. Good for mileage, but bad for engines when it's too lean.

Wouldn't a blown head gasket turn the oil white milky?

Not always, it depends on where the gasket blows out. It could blow to the outside air, the oil return (causing cloudy oil), or the cooling jackets. Sometimes they only blow out between combustion chambers.

Ok wow, I didn't know that. Are there any visual symptoms to that? Or just motor giving up? I did check my oil, is clean but smells like gas... Idk what that means but I did get it to idle a lil bit ago, with misfires. Cylinder 8,6,&2 this time. Then just like you said over pressurized hose let go and sprayed on the exhaust. So I kinda just want to yank the entire engine out and use it to prop my feet up on when I'm taking ****. I'm very frustrated. And I hate plastic. And I hate all the sensors and electronics. MAF!