1988 w100 fuel injected 318. I have replaced the gas tank fuel pump and in line fuel filter. Truck idles fine even when cold. Obviously truck stalls when cold started but will stall after 30 min idle in drive trying to drive and get up to speed. will not stall at speed just when you begin to drive. It also will stall in reverse when you need to give it more gas to go uphill. Most of the time i let the choke just drive since it will tend to go without giving it gas. Any thoughts?

 

I am now thinking it may be a faulty TPS. Which i replaced but not have an entirely different issue regarding extremely high idle, almost gunning it high. I disconnected the battery to reset anything, which i don't think is needed, but don't know if i installed the TPS wrong. When inserting the TPS into the throttle you need to maintain pressure on the sensor and turn it clockwise to line up the two bolts. I am thinking maybe i put too much pressure and need to reinstall the TPS. Have any of you had this issue before?

 

You have checked the fuel pressure, and the condition of the lines?

 

i can tonight, but my initial issue was the low oil pressure so i assumed the TPS was the cause since at idle it was find but had issues when driving and coming to a stop it would stall or have a severe drop in oil pressure with the oil light coming on. i recently replaced the fuel pump because it was starving for fuel and would barely get up to speed. That fixed that issue but now the low oil pressure started the TPS replacement which now is the crazy high idle.

 

My 87 is carbureated. My fuel intake, return, and vapor lines were all rotted. Along with the brake lines. Size them before ordering, wish I did. Use hi pressure fuel line and clamps.
PO had put on a new mechanical fuel pump, then punted.
I have read aluminum lines are subject to cracking.