I own a 1988 F-150 5.0 Automatic Trans and 4:10 gears. The motor is new but I had the truck sitting up for 18 months and only starting it but not moving it at least 4 times during the time she has been sitting. Every time I start the truck when it is cold and it does not matter if it has sat overnight or 8 hours at work it misses big time on start up.
I have to let it idle for about 5 minutes and I can hear cylinders coming in like it is finally firing off. I have heard at least 3 cylinders do this and once the truck warms up it runs fine with no miss even at highway speeds.
No codes are showing up and the check engine light comes on when starting it but goes out like normal after start up.
Any suggestions would be appreciated.

 

How is the throttle body and the air bypass valve? Is there any ticking? Try to run some fuel system treatment, or might be sticky injectors until engine warms up.

 

I will try running some fuel treatment and see what happens makes sense since the truck has been sitting up for 18 months.
Will let you know.
Thank you,

 

np.