1.6 16V NO LOAD miss from 1000 to 3000 R.P.M.

[Lon]

sorry for your plight !!

CEL out running? check engine light out?

its rich misfiring, and probably not holding closed loop at cursing (Sigmund Freud was here).
The oxy sensor is not working (is exhaust head tube 4 cracked) or bottom header collector donut gasket bad, sucking in air?
it may be in limphome mode, too.
is MPG bad? (horrid)

1: IS ENGINE FULLY HOT, 180f MIN?
2: is CEL out.
3: is 02 new? less than 100,000 miles old?
4: is exh. cracked or leaking before the CAT.
5: huge air leak in the total air intake path? examine with eyes, there can be no leaks behind the FAM sensor or it can go lean.
is the ECU flashing code 12?

Thanks for your reply and help
First off, car has Headman headers.
mileage is 24.5 .........freeway, city and puttin around the dairy in 1st & 2nd gear
O2 sensor is 2 years old
water temp .... looking at the temp gage as if it were a fuel gage, it MIGHT get to 1/4 tank.
previous owner tells me radiator is from a car with A/C , car has no A/C , also has no stock fan or fan shroud. has 14" electric fan, but no reason to run it.
Exhaust . I do not hear any leaks at the header to exhaust pipe joint.
but if the headers were designed to run "open" a leak should not effect the O2 sensor , right?
Intake system is in good condition
don't understand "CEL"
no "check engine" light
where do I look to see "ECU flashing 12" ?
added a ground wire from the battery to the engine, tightened the + battery cable and covered about 1/3ed of the radiator with cardboard. No changes
may be a bad thermostat.

Again .THANKS FOR THE HELP !!!!!!!!!!