hello I have a question about the 300 6 motor well the computer to be specific we used to have a 91 f150 4x4 with the 4 speed and the 300 6 now we have an 87 f150 4x4 with the 4 speed and the 300 6 my question is this the 91 seems to have more power when pulling same tranny same motor why would this be. Is there some difference in the programming for fuel delivery because the 87 was the first year for the fuel injection system or what and if so could I then take the computer out of a 91 and gain that extra little bit of power or is there really no difference thanks in advance for any advice

 

There is a calibration code on the driver side door jamb..if it is no longer there have a dealer decode the vin # and tell you the correct cpu for your truck...There are like 9 diff cpus for 1990's...I assume it will be the same for yours.

 

Why do you think that the computer is to blame. No two engines are exactly alike, especially after some wear and tear. I would think the the two eecs would have very minor differences. What rear end gear was in both trucks? Gearing could make one feel more powerful than the other.

 

i dont think the cpu is to blame just a general wondering about the ecm