1991 Ford Escort engine runs erratic when cold

Hi kool_rider, Welcome to 2carpros and TY for the donation

Test the engine coolant temperature sensor and clean out the idle air control valve and EGR/PCV valves and clean the MAF sensor with an electronic cleaner CRC, and also test the throttle position sensor-

I tried what you said, replaced the coolant temperature sensor; removed the idle control valve, cleaned and reinstalled it; checked the EGR/PCV valves; cleaned the MAF sensor and checked the throttle position sensor. It is now running BAD all the time. More on the engine, it has 370,000 km on it, its using oil (burning it) at the rate of 1 L a week. It runs ok with NO throttle and clears out with WIDE OPEN throttle. At light throttle between 60 - 100 km/hr it surges, almost hunts for an up shift, shakes and clunks the car. These are at highway speeds. Its almost undriveable. Could there be a problem with the fuel injection system? Maybe a bad injector or is it the computer?

thanks,
Clint

Inspect the spark plugs could be carboned -up and do a fuel pressure check

I started pulling off spark plug wires, and 2 of them separated at the end from the connector, and I think this was my problem. There was not a positive connection between the core of the wire and the metal end, resulting in erratic plug firing. I installed new spark plugs and wires, and the car now runs great! Thanks for all your advice, I was scratching my head for weeks now wondering what the problem could be, and it turned out to be a really simple solution.

Clint