does anyone know the fitting size for the inlet on the fuel pre heater on a 96 12v.

I replaced the fuel lift pump and 1/2" line (which had a large crack) that run between the pre heater and lift pump. the truck runs now but has intermittent rpm drops.
the line that runs from the lift pump to the fuel filter had a fitting on the lift pump that wouldnt break lose so i had to remove the line with the pump. I couldnt even break it free on the bench so I will make a replacement. I will also r3eplace the feed line to the pre heater.

 

1/2in NPT

 

Theres no preheater. Are you talking about the prefilter or the heater?

 

the fuel heater feed line.
thx MacAttack
The truck starts hard then runs great for about 10 minutes then it developes a miss at steady intervals...if i push the peddle it will hesitste for a bit and then smooth out. Not sure if it runns good while the filter is full and then starves or if its jusst air slowly building up. but because its so hard starting i am guessing air getting in somewhere. first thing i will change tho is the water in fuel sensor because that definately has a small leak.
I will also start replacing injector lines...a couple are rusted bad but not leaking yet. does anyone know where I can buy lines one at a time?

 

going INTO the prefilter/preheater is 3/8 NPT...
I replaced mine w/ 3/8 NPT to 3/8 hose and got rid of the tubing.

Going INTO the pump from the prefilter/preheater is 1/2 hose to 1/2 NTP