1999 Ford Mustang Question: I hate computers in cars!!

My vehicle starts with my computer. BUT while I am driving I lose power and my CHECK ENGINE LIGHT would start flashing at me. I had a friend unhook my battery BEFORE we could check codes. So now MY CURRENT computer will no longer set off my check engine light at all. My repairman put a fuel pressure gauge on and I was getting inconsistent pressure. My spark plugs are also showing signs of lack of fuel. If my computer is not functioning do we still FLASH is though? and how do you flash a computer for a car? They are replacing he fuel pump as I type, but he called to tell me my fuel smelled bad and asked if I was putting E-85 in (which I am not). He is checking to see if there is evidence of someone placing something in my fuel tank also. I have replaced the fuel filter with a brand new NAPA one as well.

ok, we are on the same track. if the fuel smells bad, then now is the time to dump the tank and add new.
a new pump will increase your pressure and it will run better.
the check engine light was telling you a missfire. you need to read the code. clearing it does nothing. the problem is still there. get the code read when it comes on again as when you took off the battery cable you wiped out all the info needed to check the code.

flashing requires a scan tool and a shop with the capability to update your computer info by going to the ford web site and getting the most up to date info. can you do it yourself, no, unless you have the 4000 tool. it costs about 180 to flash it and with the age of your car, it may have several updates.

Roy