Hard Start cold, Hesitation in 1st & 2nd

[ptofimpact]

1989 Ranger, Manual 5 speed,64000 Orig miles. Hard start cold, cycle key several times to prime, then starts.
When trying to accelarate, Hesitation and bucking, cannot get over 20MPH. New Plugs, Cap, Rotor, Wires, PCV, Fuel filter.
Did KOEO- first time code 87-Fuel Pump Primary circuit failure. Next day same test, Clean Code 11
Did KOER- Performed WOT at Code 10; Got a Code 21- Engine Coolant Temp Sensor out of Range.

Not sure where to start, I suppose Temp sensor, easiest and cheapest to try,any direction appreciated.

 

[kimcrwbr1]

Replace the Coolant temp sensor and clean the intake air tem sensor at the same time. While your doing that disconnect the battery for at least 1/2 an hour to reset the computer. use maf or elect cleaner for the intake air temp(IAT) then run it for a complete warm up cycle and see how it runs. If it still cold starts hard check the TPS throttle position sensor clean the idle air control solenoid and the throttle body around the throttle plate and then again reset the computer for giggles while your working on it. It takes at least 20 mins at medium speeds for the computer to set the new values so go through a couple complete warmups to check the codes. It is also helpful to erase the computer memory before you reset the computer so your not chasing false codes. Always fix the lowest number code first erase the memory and reset the computer and test again to confirm the repair. Then move on to the next one if any and always warm the engine all the way up before running the codes.

 

[ptofimpact]

Thanks

kimcrwbr1
Thanks for the reply, bought the coolant temp sensor, and cleaner.
Did the cleaning part, now have to locate a socket to fit the sensor.
Appreciate the direction.

 

[ptofimpact]

Resolution

Hi all, the final solution, after replacing Coolant Temp sensor, plugs, wires, cap, rotor button, fuel filter, pvc valve, clean throttle body............
Had to replace the Fuel Pump and Strainer, which is in the Fuel Tank.
Thanks to all for the great suggestions and assistance.