2000 deville misfire

[back2life]

my 2000 deville (which i never drive) but start up and let run decided to give a BIG problem today. i went to charge my a/c up and when i started it it was running very rough...last week it did it also but after letting it run it smoothed out but today it stayed same and was actually worse. i drove it around the block and check engine light was flashing and car was sputtering like it didnt want to go. sputtering out of exhaust and exhaust was gettin real hot and giving off smoke from behind tires area. it was actually starting to burn my grass. i dont understand why it would do this all of a sudden. i pulled codes and this is what was there

p01571

u1040

u1064

u1192

the only code that is usually in there is the tcc code and its been for years..i need help please!!!

[back2life]

i went back and got codes from on board diagnostics p0300 p1571 u1040 u1064 u1066 01300 also my abs,brake and traction lights are sitting on now also

[maxwedge]

0300 misfire, plugs, wire, coil, low fuel pressure, don't run it like this, you will burn up the cat if not done already, fix that first then clear the codes.

[back2life]

I took front plugs out and they still look nice and dont smell like gas either?? No oil on boots and no cracks or carbon either. How do i test coil packs? And do you think it could be a computer failure??

[maxwedge]

If it is missing at idle, try and short or ground one wire at a time see if the miss doesn't change then that is the cylinder that is missing. Unplug one injector at a time if you can, same test, you can look at rpm changes with a scanner or dash tach, as you do this when no change that is the cylinder misfiring, if you can get it to miss at idle, or with a good scanner look at misfire counts to pin it down, also check fuel pressure at the rail port,this not an easy diagnosis.

[back2life]

thanks maxwedge for your help.... heres what i looked at today, when key turned on the fuel pressure jumps to bout 45 then instantly drops back to like 36-38 lbs...while running it is about 40-42 lbs. i tried a usd ecm and got no start (shoulda known that wouldnt work) but hell i tried anyway lol pulled the wire from injectors one at a time and only noticed a difference on like 3 or 4. running so bad its hard to tell. unplugged mass sensor while running and it ran better but still the same.