I may have narrowed it down to the fuel cap I have.
Long story short, after some time on the highway the truck will begin to aggressively chug, pop, spit, and backfire out of the carb. however, if i put it in neutral and rev it, its perfectly fine. revs up normal. pop it back into drive, immediately back to stumbling. at first i thought it was the fuel pump going out, so i replaced it (it had some age to it, and i did not replace it when i put a timing chain on the truck) and previously went through the carb. both of those did not fix it, but i noticed when i take the fuel feed hose off of the pump (the line from the tank), it is gushing out as hard as the average faucet and would seemingly empty the contents of a full tank if left to drain. my regal doesnt have this problem, its usually no more than a half cup maybe. so I got to thinking, did i buy the wrong gas cap? there are vented caps for the non evap system trucks and nonvented for the trucks with that system. i have a non vented cap in a vented system.
I think the fuel system is under a lot more pressure than i should be and its either overloading the needle and seat on the qjet and just drowning the carb (entire top of carb ends up being wet with fuel), or its pseudo vapor locking itself and free revving it kind of clears it up a bit.
I'm gonna pick up a vented cap tomorrow and see what that does. the truck had a vented cap on it when i got it, but the tweakers before me ****ed up the lock and i almost broke a key trying to take it off once. i needed a cap, and the non vented is all the store had at the time.
it's either come down to the cap, or maybe an intermittent spark problem. it has a new duraspark box and coil, wiring, plugs, wires, etc from when i did a tune up last year.
i still dont understand why it will rev up fine in neutral but in drive it goes back to sputtering. only does it with sustained highway rpm, or if i mat it from a stop light it will just cut out and almsot die if i dont back out of it in time.
even though its a ford, i know a few of you have owned these trucks or at least know someone who has. any input is appreciated.
Long story short, after some time on the highway the truck will begin to aggressively chug, pop, spit, and backfire out of the carb. however, if i put it in neutral and rev it, its perfectly fine. revs up normal. pop it back into drive, immediately back to stumbling. at first i thought it was the fuel pump going out, so i replaced it (it had some age to it, and i did not replace it when i put a timing chain on the truck) and previously went through the carb. both of those did not fix it, but i noticed when i take the fuel feed hose off of the pump (the line from the tank), it is gushing out as hard as the average faucet and would seemingly empty the contents of a full tank if left to drain. my regal doesnt have this problem, its usually no more than a half cup maybe. so I got to thinking, did i buy the wrong gas cap? there are vented caps for the non evap system trucks and nonvented for the trucks with that system. i have a non vented cap in a vented system.
I think the fuel system is under a lot more pressure than i should be and its either overloading the needle and seat on the qjet and just drowning the carb (entire top of carb ends up being wet with fuel), or its pseudo vapor locking itself and free revving it kind of clears it up a bit.
I'm gonna pick up a vented cap tomorrow and see what that does. the truck had a vented cap on it when i got it, but the tweakers before me ****ed up the lock and i almost broke a key trying to take it off once. i needed a cap, and the non vented is all the store had at the time.
it's either come down to the cap, or maybe an intermittent spark problem. it has a new duraspark box and coil, wiring, plugs, wires, etc from when i did a tune up last year.
i still dont understand why it will rev up fine in neutral but in drive it goes back to sputtering. only does it with sustained highway rpm, or if i mat it from a stop light it will just cut out and almsot die if i dont back out of it in time.
even though its a ford, i know a few of you have owned these trucks or at least know someone who has. any input is appreciated.